TY - JOUR AU - Simon, Márton AU - Iordanov, Iordan AU - Szöllősi, András AU - Csanády, László TI - Estimating the true stability of the prehydrolytic outward-facing state in an ABC protein. JF - ELIFE J2 - ELIFE VL - 12 PY - 2023 PG - 19 SN - 2050-084X DO - 10.7554/eLife.90736 UR - https://m2.mtmt.hu/api/publication/34232792 ID - 34232792 AB - CFTR, the anion channel mutated in cystic fibrosis patients, is a model ABC protein whose ATP-driven conformational cycle is observable at single-molecule level in patch-clamp recordings. Bursts of CFTR pore openings are coupled to tight dimerization of its two nucleotide-binding domains (NBDs) and in wild-type (WT) channels are mostly terminated by ATP hydrolysis. The slow rate of non-hydrolytic closure - which determines how tightly bursts and ATP hydrolysis are coupled - is unknown, as burst durations of catalytic site mutants span a range of ~200-fold. Here, we show that Walker A mutation K1250A, Walker B mutation D1370N, and catalytic glutamate mutations E1371S and E1371Q all completely disrupt ATP hydrolysis. True non-hydrolytic closing rate of WT CFTR approximates that of K1250A and E1371S. That rate is slowed ~15-fold in E1371Q by a non-native inter-NBD H-bond, and accelerated ~15-fold in D1370N. These findings uncover unique features of the NBD interface in human CFTR. LA - English DB - MTMT ER - TY - JOUR AU - Mihályi, Csaba AU - Iordanov, Iordan AU - Törőcsik, Beáta AU - Csanády, László TI - Simple binding of protein kinase A, prior to phosphorylation, allows CFTR anion channels to be opened by nucleotides JF - PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA J2 - P NATL ACAD SCI USA VL - 117 PY - 2020 IS - 35 SP - 21740 EP - 21746 PG - 7 SN - 0027-8424 DO - 10.1073/pnas.2007910117 UR - https://m2.mtmt.hu/api/publication/31397038 ID - 31397038 LA - English DB - MTMT ER - TY - JOUR AU - Tóth, Balázs AU - Iordanov, Iordan AU - Csanády, László TI - Selective profiling of N- And C-terminal nucleotide-binding sites in a TRPM2 channel JF - JOURNAL OF GENERAL PHYSIOLOGY J2 - J GEN PHYSIOL VL - 152 PY - 2020 IS - 5 PG - 13 SN - 0022-1295 DO - 10.1085/jgp.201912533 UR - https://m2.mtmt.hu/api/publication/31365406 ID - 31365406 N1 - Department of Medical Biochemistry, Semmelweis University, Budapest, Hungary MTA-SE Lendület Ion Channel Research Group, Semmelweis University, Budapest, Hungary Cited By :7 Export Date: 15 September 2021 CODEN: JGPLA Correspondence Address: Tóth, B.; Department of Medical Biochemistry, Hungary; email: toth.balazs@med.semmelweis-univ.hu Chemicals/CAS: adenosine diphosphate ribose, 20762-30-5; amino acid, 65072-01-7; calcium, 7440-70-2, 14092-94-5; Adenosine Diphosphate Ribose; Amino Acids; Calcium; Ligands; Nucleotides; TRPM Cation Channels; TRPM2 protein, human Funding details: Semmelweis Egyetem, 18-4-SE-132, 19-4-SE-49 Funding details: Magyar Tudományos Akadémia, MTA, LP2017-14/2017 Funding text 1: Supported by the Hungarian Academy of Sciences (Lendület grant LP2017-14/2017 to L. Csanády) and a Ministry of Human Capacities of Hungary New National Excellence Program (Új Nemzeti Kiválóság Program) award to Semmelweis University. B. Tóth is a János Bolyai Research Fellow, supported by postdoctoral Új Nemzeti Kiválóság Program grants 18-4-SE-132 and 19-4-SE-49. The authors declare no competing financial interests. AB - Transient receptor potential melastatin 2 (TRPM2) is a homotetrameric Ca2+-permeable cation channel important for the immune response, body temperature regulation, and insulin secretion, and is activated by cytosolic Ca2+ and ADP ribose (ADPR). ADPR binds to two distinct locations, formed by large N- and C-terminal cytosolic domains, respectively, of the channel protein. In invertebrate TRPM2 channels, the C-terminal site is not required for channel activity but acts as an active ADPR phosphohydrolase that cleaves the activating ligand. In vertebrate TRPM2 channels, the C-terminal site is catalytically inactive but cooperates with the N-terminal site in channel activation. The precise functional contributions to channel gating and the nucleotide selectivities of the two sites in various species have not yet been deciphered. For TRPM2 of the sea anemone Nematostella vectensis (nvTRPM2), catalytic activity is solely attributable to the C-terminal site. Here, we show that nvTRPM2 channel gating properties remain unaltered upon deletion of the C-terminal domain, indicating that the N-terminal site is single-handedly responsible for channel gating. Exploiting such functional independence of the N- and C-terminal sites, we selectively measure their affinity profiles for a series of ADPR analogues, as reflected by apparent affinities for channel activation and catalysis, respectively. Using site-directed mutagenesis, we confirm that the same N-terminal site observed in vertebrate TRPM2 channels was already present in ancient cnidarians. Finally, by characterizing the functional effects of six amino acid side chain truncations in the N-terminal site, we provide first insights into the mechanistic contributions of those side chains to TRPM2 channel gating. © 2020 Tóth et al. This article is distributed under the terms of an Attribution-Noncommercial-Share Alike-No Mirror Sites license for the first six months after the publication date (see http://www.rupress.org/terms/). After six months it is available under a Creative Commons License (Attribution-Noncommercial-Share Alike 4.0 International license, as described at https://creativecommons.org/licenses/by-nc-sa/4.0/). LA - English DB - MTMT ER - TY - JOUR AU - Iordanov, Iordan AU - Tóth, Balázs AU - Szöllősi, András AU - Csanády, László TI - Enzyme activity and selectivity filter stability of ancient TRPM2 channels were simultaneously lost in early vertebrates JF - ELIFE J2 - ELIFE VL - 8 PY - 2019 IS - 2019 PG - 23 SN - 2050-084X DO - 10.7554/eLife.44556 UR - https://m2.mtmt.hu/api/publication/30637149 ID - 30637149 N1 - Funding Agency and Grant Number: Howard Hughes Medical InstituteHoward Hughes Medical Institute; Magyar Tudomanyos Akademia [LP2017-14/2017]; Ministry of Human Capacities of Hungary [UNKP 17-4-I-SE-61, UNKP 18-4-SE-132]; Magyar Tudomanyos Akademia Funding text: Howard Hughes Medical Institute International Early Career Scientist Award Laszlo Csanady; Magyar Tudomanyos Akademia LP2017-14/2017 Laszlo Csanady; Ministry of Human Capacities of Hungary UNKP 17-4-I-SE-61 Balazs Toth; Magyar Tudomanyos Akademia Bolyai Research Fellowship Balazs Toth; Ministry of Human Capacities of Hungary UNKP-FIKP Laszlo Csanady; Ministry of Human Capacities of Hungary UNKP 18-4-SE-132 Balazs Toth; The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication. Export Date: 7 January 2020 Correspondence Address: Csanády, L.; Department of Medical Biochemistry, Semmelweis UniversityHungary; email: csanady.laszlo@med.semmelweis-univ.hu Export Date: 8 January 2020 Correspondence Address: Csanády, L.; Department of Medical Biochemistry, Semmelweis UniversityHungary; email: csanady.laszlo@med.semmelweis-univ.hu AB - Transient Receptor Potential Melastatin 2 (TRPM2) is a cation channel important for the immune response, insulin secretion, and body temperature regulation. It is activated by cytosolic ADP ribose (ADPR) and contains a nudix-type motif 9 (NUDT9)-homology (NUDT9-H) domain homologous to ADPR phosphohydrolases (ADPRases). Human TRPM2 (hsTRPM2) is catalytically inactive due to mutations in the conserved Nudix box sequence. Here, we show that TRPM2 Nudix motifs are canonical in all invertebrates but vestigial in vertebrates. Correspondingly, TRPM2 of the cnidarian Nematostella vectensis (nvTRPM2) and the choanoflagellate Salpingoeca rosetta (srTRPM2) are active ADPRases. Disruption of ADPRase activity fails to affect nvTRPM2 channel currents, reporting a catalytic cycle uncoupled from gating. Furthermore, pore sequence substitutions responsible for inactivation of hsTRPM2 also appeared in vertebrates. Correspondingly, zebrafish (Danio rerio) TRPM2 (drTRPM2) and hsTRPM2 channels inactivate, but srTRPM2 and nvTRPM2 currents are stable. Thus, catalysis and pore stability were lost simultaneously in vertebrate TRPM2 channels. LA - English DB - MTMT ER - TY - JOUR AU - Saurel, O AU - Iordanov, Iordan AU - Nars, G AU - Demange, P AU - Le Marchand, T AU - Andreas, LB AU - Pintacuda, G AU - Milon, A TI - Local and Global Dynamics in Klebsiella pneumoniae Outer Membrane Protein a in Lipid Bilayers Probed at Atomic Resolution JF - JOURNAL OF THE AMERICAN CHEMICAL SOCIETY J2 - J AM CHEM SOC VL - 139 PY - 2017 IS - 4 SP - 1590 EP - 1597 PG - 8 SN - 0002-7863 DO - 10.1021/jacs.6b11565 UR - https://m2.mtmt.hu/api/publication/3341707 ID - 3341707 AB - The role of membrane proteins in cellular mechanism strongly depends on their dynamics, and solid-state magic-angle spinning (MAS) nuclear magnetic resonance (NMR) is a unique method to exhaustively characterize motions of proteins in a lipid environment. Herein, we make use of advances in H-1-detected MAS NMR to describe the dynamics of the membrane domain of the Outer membrane protein A of Klebsiella pneumoniae (KpOmpA). By measuring H-1-N-15 dipolar coupling as well as N-15 R-1 and R-1 rho relaxation rates at fast (60 kHz) MAS and high magnetic field (1 GHz), we were able to describe the motions of the residues of the beta-barrel as a collective rocking of low amplitude and of hundreds of nanoseconds time scale. Residual local motions at the edges of the strands, underscored by enhanced (NT)-N-15 R-1 rho relaxation rates, report on the mobility of the connected loops. In agreement with MAS NMR data, proteolysis experiments performed on the full length KpOmpA as well as on its membrane domain, reconstituted in liposomes or in detergent micelles, revealed in all cases the existence of a unique trypsin cleavage site within the membrane domain (out of 16 potential Lys and Arg sites). This site is located in the extracellular loop L3, showing that it is highly accessible to protein-protein interactions. KpOmpA is involved in cell-cell recognition, for adhesion and immune response mechanisms. The L3 region may therefore play a key role in pathogenicity. LA - English DB - MTMT ER - TY - JOUR AU - Németh, Beáta AU - Dóczi, Judit AU - Csete, Dániel AU - Kacsó, Gergely AU - Ravasz, Dóra AU - Daniel, Adams AU - Kiss, Gergely AU - Nagy, Ádám Miklós AU - Horváth, Gergő AU - Tretter, László AU - Mócsai, Attila AU - Csépányi-Kömi, Roland AU - Iordanov, Iordan AU - Ádám, Veronika AU - Chinopoulos, Christos TI - Abolition of mitochondrial substrate-level phosphorylation by itaconic acid produced by LPS-induced Irg1 expression in cells of murine macrophage lineage JF - FASEB JOURNAL J2 - FASEB J VL - 30 PY - 2016 IS - 1 SP - 286 EP - 300 PG - 15 SN - 0892-6638 DO - 10.1096/fj.15-279398 UR - https://m2.mtmt.hu/api/publication/2940351 ID - 2940351 LA - English DB - MTMT ER - TY - JOUR AU - Iordanov, Iordan AU - Mihályi, Csaba AU - Tóth, Balázs AU - Csanády, László TI - The proposed channel-enzyme transient receptor potential melastatin 2 does not possess ADP ribose hydrolase activity JF - ELIFE J2 - ELIFE VL - 5 PY - 2016 PG - 20 SN - 2050-084X DO - 10.7554/eLife.17600 UR - https://m2.mtmt.hu/api/publication/3105008 ID - 3105008 N1 - Department of Medical Biochemistry, Semmelweis University, Budapest, Hungary MTA-SE Ion Channel Research Group, Semmelweis University, Budapest, Hungary Cited By :17 Export Date: 20 September 2019 Correspondence Address: Csanády, L.; Department of Medical Biochemistry, Semmelweis UniversityHungary; email: csanady.laszlo@med.semmelweis-univ.hu Funding Agency and Grant Number: Howard Hughes Medical Institute International Early Career Scientist [55007416]; Magyar Tudomanyos Akademia Lendulet [LP2012-39/2012] Funding text: Howard Hughes Medical Institute International Early Career Scientist grant, 55007416 Laszlo Csanady; Magyar Tudomanyos Akademia Lendulet grant, LP2012-39/2012 Laszlo Csanady Export Date: 7 January 2020 Correspondence Address: Csanády, L.; Department of Medical Biochemistry, Semmelweis UniversityHungary; email: csanady.laszlo@med.semmelweis-univ.hu LA - English DB - MTMT ER - TY - JOUR AU - Kacsó, Gergely AU - Ravasz, Dóra AU - Dóczi, Judit AU - Németh, Beáta AU - Madgar, O AU - Saada, A AU - Ilin, P AU - Miller, C AU - Ostergaard, E AU - Iordanov, Iordan AU - Adams, D AU - Vargedo, Z AU - Araki, M AU - Araki, K AU - Nakahara, M AU - Ito, H AU - Gál, Anikó AU - Molnár, Mária Judit AU - Nagy, Zsolt AU - Patócs, Attila Balázs AU - Ádám, Veronika AU - Chinopoulos, Christos TI - Two transgenic mouse models for beta subunit components of succinate-CoA ligase yielding pleiotropic metabolic alterations JF - BIOCHEMICAL JOURNAL J2 - BIOCHEM J VL - 473 PY - 2016 IS - 20 SP - 3463 EP - 3485 PG - 23 SN - 0264-6021 DO - 10.1042/BCJ20160594 UR - https://m2.mtmt.hu/api/publication/3099231 ID - 3099231 N1 - Department of Medical Biochemistry, Semmelweis University, Tuzolto street 37-47, Budapest, 1094, Hungary MTA-SE Lendület Neurobiochemistry Research Group, Budapest, 1094, Hungary Monique and Jacques Roboh Department of Genetic Research, Hadassah-Hebrew University Medical Center, Jerusalem, 91120, Israel Department of Clinical Genetics, Copenhagen University Hospital Rigshospitalet, Copenhagen, 2100, Denmark MTA-SE Lendület Ion Channel Research Group, Budapest, 1094, Hungary Institute of Resource Development and Analysis, Kumamoto University, 2-2-1 Honjo, Chuo-ku, Kumamoto, 860-0811, Japan Institute of Genomic Medicine and Rare Disorders, Semmelweis University, Budapest, 1083, Hungary MTA-SE Lendület Hereditary Endocrine Tumours Research Group, Budapest, 1088, Hungary MTA-SE Laboratory for Neurobiochemistry, Budapest, 1094, Hungary Cited By :11 Export Date: 6 January 2021 CODEN: BIJOA Department of Medical Biochemistry, Semmelweis University, Tuzolto street 37-47, Budapest, 1094, Hungary MTA-SE Lendület Neurobiochemistry Research Group, Budapest, 1094, Hungary Monique and Jacques Roboh Department of Genetic Research, Hadassah-Hebrew University Medical Center, Jerusalem, 91120, Israel Department of Clinical Genetics, Copenhagen University Hospital Rigshospitalet, Copenhagen, 2100, Denmark MTA-SE Lendület Ion Channel Research Group, Budapest, 1094, Hungary Institute of Resource Development and Analysis, Kumamoto University, 2-2-1 Honjo, Chuo-ku, Kumamoto, 860-0811, Japan Institute of Genomic Medicine and Rare Disorders, Semmelweis University, Budapest, 1083, Hungary MTA-SE Lendület Hereditary Endocrine Tumours Research Group, Budapest, 1088, Hungary MTA-SE Laboratory for Neurobiochemistry, Budapest, 1094, Hungary Cited By :12 Export Date: 9 September 2021 CODEN: BIJOA Funding Agency and Grant Number: Lendulet grant of the Hungarian Academy of Sciences [LP2012-39/2012]; Danish National Health Research Council [12-127702]; Hadassah research grant [TAMOP 4.2.1./B-09/1/KMR, BIOINF09TET_10-1-2011-0058]; Orszagos Tudomanyos Kutatasi Alapprogram (OTKA) grant [81983]; Hungarian Academy of SciencesHungarian Academy of Sciences [02001]; Hungarian Brain Research Program [KTIA_13_NAP-A-III/6]; MTA-SE 'Hereditary' Endocrine Tumours Research Group; MTA-SE Lendulet Neurobiochemistry Research Division [95003]; OTKAOrszagos Tudomanyos Kutatasi Alapprogramok (OTKA) [NNF 78905, NNF2 85658, K 100918] Funding text: This work was supported by the Lendulet grant LP2012-39/2012 of the Hungarian Academy of Sciences to Laszlo Csanady, the Danish National Health Research Council grant [12-127702 to E.O.]; a compensatory Hadassah research grant to A.S. [TAMOP 4.2.1./B-09/1/KMR and BIOINF09TET_10-1-2011-0058 to M.J.M.]; the Orszagos Tudomanyos Kutatasi Alapprogram (OTKA) grant [81983], the Hungarian Academy of Sciences grant [02001], the Hungarian Brain Research Program [KTIA_13_NAP-A-III/6] to V.A.-V., a grant of MTA-SE 'Hereditary' Endocrine Tumours Research Group to A.P. and grants MTA-SE Lendulet Neurobiochemistry Research Division [95003], OTKA [NNF 78905], OTKA [NNF2 85658] and OTKA [K 100918] to C.C. Part number: 20 AB - Succinate-CoA ligase is a heterodimer enzyme composed of Suclg1 -alpha- and a substrate-specific Sucla2 or Suclg2 -beta- subunit yielding ATP or GTP, respectively. In humans, the deficiency of this enzyme leads to encephalomyopathy with, or without methylmalonyl aciduria, in addition to resulting in mitochondrial DNA depletion. We generated mice lacking either one Sucla2 or Suclg2 allele. Sucla2 heterozygote mice exhibited tissue- and age-dependent decreases in Sucla2 expression associated with decreases in ATP-forming activity, but rebound increases in cardiac Suclg2 expression and GTP-forming activity. Bioenergetic parameters including substrate-level phosphorylation were not different between wild type and Sucla2 heterozygote mice unless a submaximal pharmacological inhibition of succinate-CoA ligase was concomitantly present. mtDNA contents were moderately decreased, but blood carnitine esters were significantly elevated. Suclg2 heterozygote mice exhibited decreases in Suclg2 expression but no rebound increases in Sucla2 expression or changes in bioenergetic parameters. Surprisingly, deletion of one Suclg2 allele in Sucla2 heterozygote mice still led to a rebound but protracted increase in Suclg2 expression, yielding double heterozygote mice with no alterations in GTP-forming activity or substrate-level phosphorylation, but more pronounced changes in mtDNA content and blood carnitine esters, and an increase in succinate dehydrogenase activity. We conclude that a partial reduction in Sucla2 elicits rebound increases in Suclg2 expression which is sufficiently dominant to overcome even a concomitant deletion of one Suclg2 allele, pleiotropically affecting metabolic pathways associated with succinate-CoA ligase. These results as well as the availability of the transgenic mouse colonies will be of value in understanding succinate-CoA ligase deficiency. LA - English DB - MTMT ER - TY - JOUR AU - Tóth, Balázs AU - Iordanov, Iordan AU - Csanády, László TI - Ruling out pyridine dinucleotides as true TRPM2 channel activators reveals novel direct agonist ADP-ribose-2'-phosphate JF - JOURNAL OF GENERAL PHYSIOLOGY J2 - J GEN PHYSIOL VL - 145 PY - 2015 IS - 5 SP - 419 EP - 430 PG - 12 SN - 0022-1295 DO - 10.1085/jgp.201511377 UR - https://m2.mtmt.hu/api/publication/2949645 ID - 2949645 N1 - Funding Agency and Grant Number: International Early Career Scientist grant from the Howard Hughes Medical InstituteHoward Hughes Medical Institute; MTA Lendulet grant [LP2012-39/2012] Funding text: This work is supported by an International Early Career Scientist grant from the Howard Hughes Medical Institute to L. Csanady, and MTA Lendulet grant LP2012-39/2012. Export Date: 7 January 2020 CODEN: JGPLA Correspondence Address: Csanády, L.; Department of Medical Biochemistry, Semmelweis UniversityHungary; email: csanay.laszlo@med.semmelweis-univ.hu AB - Transient receptor potential melastatin 2 (TRPM2), a Ca(2+)-permeable cation channel implicated in postischemic neuronal cell death, leukocyte activation, and insulin secretion, is activated by intracellular ADP ribose (ADPR). In addition, the pyridine dinucleotides nicotinamide-adenine-dinucleotide (NAD), nicotinic acid-adenine-dinucleotide (NAAD), and NAAD-2'-phosphate (NAADP) have been shown to activate TRPM2, or to enhance its activation by ADPR, when dialyzed into cells. The precise subset of nucleotides that act directly on the TRPM2 protein, however, is unknown. Here, we use a heterologously expressed, affinity-purified-specific ADPR hydrolase to purify commercial preparations of pyridine dinucleotides from substantial contaminations by ADPR or ADPR-2'-phosphate (ADPRP). Direct application of purified NAD, NAAD, or NAADP to the cytosolic face of TRPM2 channels in inside-out patches demonstrated that none of them stimulates gating, or affects channel activation by ADPR, indicating that none of these dinucleotides directly binds to TRPM2. Instead, our experiments identify for the first time ADPRP as a true direct TRPM2 agonist of potential biological interest. LA - English DB - MTMT ER - TY - JOUR AU - Gater, DL AU - Saurel, O AU - Iordanov, Iordan AU - Liu, W AU - Cherezov, V AU - Milon, A TI - Two classes of cholesterol binding sites for the β2AR revealed by thermostability and NMR JF - BIOPHYSICAL JOURNAL J2 - BIOPHYS J VL - 107 PY - 2014 IS - 10 SP - 2305 EP - 2312 PG - 8 SN - 0006-3495 DO - 10.1016/j.bpj.2014.10.011 UR - https://m2.mtmt.hu/api/publication/3110346 ID - 3110346 AB - Cholesterol binding to G protein-coupled receptors (GPCRs) and modulation of their activities in membranes is a fundamental issue for understanding their function. Despite the identification of cholesterol binding sites in high-resolution x-ray structures of the β2 adrenergic receptor (β2AR) and other GPCRs, the binding affinity of cholesterol for this receptor and exchange rates between the free and bound cholesterol remain unknown. In this study we report the existence of two classes of cholesterol binding sites in β2AR. By analyzing the β2AR unfolding temperature in lipidic cubic phase (LCP) as a function of cholesterol concentration we observed high-affinity cooperative binding of cholesterol with sub-nM affinity constant. In contrast, saturation transfer difference (STD) NMR experiments revealed the existence of a second class of cholesterol binding sites, in fast exchange on the STD NMR timescale. Titration of the STD signal as a function of cholesterol concentration provided a lower limit of 100 mM for their dissociation constant. However, these binding sites are specific for both cholesterol and β2AR, as shown with control experiments using ergosterol and a control membrane protein (KpOmpA). We postulate that this specificity is mediated by the high-affinity bound cholesterol molecules and propose the formation of transient cholesterol clusters around the high-affinity binding sites. © 2014 Biophysical Society. LA - English DB - MTMT ER - TY - JOUR AU - Tóth, Balázs AU - Iordanov, Iordan AU - Csanády, László TI - Putative chanzyme activity of TRPM2 cation channel is unrelated to pore gating JF - PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA J2 - P NATL ACAD SCI USA VL - 111 PY - 2014 IS - 47 SP - 16949 EP - 16954 PG - 6 SN - 0027-8424 DO - 10.1073/pnas.1412449111 UR - https://m2.mtmt.hu/api/publication/2762109 ID - 2762109 N1 - Funding Agency and Grant Number: Howard Hughes Medical InstituteHoward Hughes Medical Institute; MTA Lendulet Grant [LP2012-39/2012] Funding text: This work was supported by an International Early Career Scientist grant from the Howard Hughes Medical Institute (to L. C.) and MTA Lendulet Grant LP2012-39/2012. Department of Medical Biochemistry, Semmelweis University, Budapest, H-1094, Hungary Magyar Tudományos Akadémia - Semmelweis Egyetem Lendület (MTA-SE), Semmelweis University, Budapest, H-1094, Hungary Cited By :25 Export Date: 7 January 2020 CODEN: PNASA Correspondence Address: Csanády, L.; Department of Medical Biochemistry, Semmelweis UniversityHungary LA - English DB - MTMT ER - TY - JOUR AU - Bosshart, PD AU - Iordanov, Iordan AU - Garzon-Coral, C AU - Demange, P AU - Engel, A AU - Milon, A AU - Müller, DJ TI - The transmembrane protein KpOmpA anchoring the outer membrane of Klebsiella pneumoniae unfolds and refolds in response to tensile load JF - STRUCTURE J2 - STRUCTURE VL - 20 PY - 2012 IS - 1 SP - 121 EP - 127 PG - 7 SN - 0969-2126 DO - 10.1016/j.str.2011.11.002 UR - https://m2.mtmt.hu/api/publication/3110796 ID - 3110796 AB - In Klebsiella pneumoniae the transmembrane β-barrel forming outer membrane protein KpOmpA mediates adhesion to a wide range of immune effector cells, thereby promoting respiratory tract and urinary infections. As major transmembrane protein OmpA stabilizes Gram-negative bacteria by anchoring their outer membrane to the peptidoglycan layer. Adhesion, osmotic pressure, hydrodynamic flow, and structural deformation apply mechanical stress to the bacterium. This stress can generate tensile load to the peptidoglycan-binding domain (PGBD) of KpOmpA. To investigate how KpOmpA reacts to mechanical stress, we applied a tensile load to the PGBD and observed a detailed unfolding pathway of the transmembrane β-barrel. Each step of the unfolding pathway extended the polypeptide connecting the bacterial outer membrane to the peptidoglycan layer and absorbed mechanical energy. After relieving the tensile load, KpOmpA reversibly refolded back into the membrane. These results suggest that bacteria may reversibly unfold transmembrane proteins in response to mechanical stress. © 2012 Elsevier Ltd. LA - English DB - MTMT ER - TY - JOUR AU - Iordanov, Iordan AU - Renault, Marie AU - Réat, Valérie AU - Bosshart, Patrick D AU - Engel, Andreas AU - Saurel, Olivier AU - Milon, Alain TI - Dynamics of Klebsiella pneumoniae OmpA transmembrane domain: The four extracellular loops display restricted motion behavior in micelles and in lipid bilayers JF - BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES J2 - BBA-BIOMEMBRANES VL - 1818 PY - 2012 IS - 9 SP - 2344 EP - 2353 PG - 10 SN - 0005-2736 DO - 10.1016/j.bbamem.2012.05.004 UR - https://m2.mtmt.hu/api/publication/3110595 ID - 3110595 AB - The transmembrane domain of Klebsiella pneumoniae OmpA (KpOmpA) possesses four long extracellular loops that exhibit substantial sequence variability throughout OmpA homologs in Enterobacteria, in comparison with the highly conserved membrane-embedded β-barrel core. These loops are responsible for the immunological properties of the protein, including cellular and humoral recognition. In addition to key features revealed by structural elucidation of the KpOmpA transmembrane domain in detergent micelles, studies of protein dynamics provide insight into its function and/or mechanism of action. We have investigated the dynamics of KpOmpA in a lipid bilayer, using magic angle spinning solid-state NMR. The dynamics of the β-barrel and loop regions were probed by the spin–lattice relaxation times of the Cα and Cβ atoms of the serine and threonine residues, and by cross-polarization dynamics. The β-barrel core of the protein is rigid; the C-terminal halves of two of the four extracellular loops (L1 and L3), which are particularly long in KpOmpA, are highly mobile. The other two loops (L2 and L4), which are very similar to their homologs in Escherichia coli OmpA, and the N-terminal halves of L1 and L3 exhibit more restricted motions. We suggest a correlation between the sequence variability and the dynamics of certain loop regions, which accounts for their respective contributions to the structural and immunological properties of the protein. LA - English DB - MTMT ER - TY - JOUR AU - Tsoneva, I AU - Iordanov, Iordan AU - Berger, AJ AU - Tomov, T AU - Nikolova, B AU - Mudrov, N AU - Berger, MR TI - Electrodelivery of drugs into cancer cells in the presence of poloxamer 188 JF - JOURNAL OF BIOMEDICINE AND BIOTECHNOLOGY J2 - J BIOMED BIOTECHNOL VL - 2010 PY - 2010 SN - 1110-7243 DO - 10.1155/2010/314213 UR - https://m2.mtmt.hu/api/publication/3110803 ID - 3110803 AB - In the present study it is shown that poloxamer 188, added before or immediately after an electrical pulse used for electroporation, decreases the number of dead cells and at the same time does not reduce the number of reversible electropores through which small molecules (cisplatin, bleomycin, or propidium iodide) can pass/diffuse. It was suggested that hydrophobic sections of poloxamer 188 molecules are incorporated into the edges of pores and that their hydrophilic parts act as brushy pore structures. The formation of brushy pores may reduce the expansion of pores and delay the irreversible electropermeability. Tumors were implanted subcutaneously in both flanks of nude mice using HeLa cells, transfected with genes for red fluorescent protein and luciferase. The volume of tumors stopped to grow after electrochemotherapy and the use of poloxamer 188 reduced the edema near the electrode and around the subcutaneously growing tumors. © 2010 Iana Tsoneva et al. LA - English DB - MTMT ER - TY - JOUR AU - Dodoff, NI AU - Iordanov, Iordan AU - Tsoneva, I AU - Grancharov, K AU - Detcheva, R AU - Pajpanova, T AU - Berger, MR TI - Cytotoxic activity of platinum(II) and palladium(II) complexes of N-3-pyridinylmethanesulfonamide: The influence of electroporation JF - ZEITSCHRIFT FÜR NATURFORSCHUNG C-A JOURNAL OF BIOSCIENCES J2 - Z NATURFORSCH C VL - 64 PY - 2009 IS - 3-4 SP - 179 EP - 185 PG - 7 SN - 0939-5075 UR - https://m2.mtmt.hu/api/publication/3110804 ID - 3110804 AB - The series of complexes: cis-[Pd(PMSA)2X2], cis-[Pt(PMSA)2X2], trans-[Pt(PMSA)2I 2] and [Pt(PMSA)4]Cl2 (PMSA = N-3-pyridinyhnethanesulfonamide; X = Cl, Br, I), previously synthesized and characterized by us, as well as the free ligand PMSA, were tested for their cytotoxic activity without electroporation - against murine leukemia F4N and human SKW-3 and MDA-MB-231 tumour cell lines - and with electroporation - against the latter two cell lines. The majority of the complexes exhibited cytotoxic effects (IC50 < 100 μmol/1) under the conditions of electroporation. Both cis- and trans-[Pt(PMSA)2I2] had pronounced cytotoxic effects (29-61 μmol/I against MDA-MB-231 cells). © 2009 Verlag der Zeitschrift für Naturforschung Tübingen. LA - English DB - MTMT ER -