TY - JOUR AU - Leitgeb, Balázs AU - Ötvös, Ferenc AU - Tóth, Géza TI - Conformational analysis of endomorphin-2 by molecular dynamics methods JF - BIOPOLYMERS J2 - BIOPOLYMERS VL - 68 PY - 2003 SP - 497 EP - 511 PG - 15 SN - 0006-3525 DO - 10.1002/bip.10333 UR - https://m2.mtmt.hu/api/publication/1912835 ID - 1912835 LA - English DB - MTMT ER - TY - JOUR AU - Vass, Elemér AU - Kurz, M AU - Konat, RK AU - Hollósi, Miklós TI - Ftir And CD Spectroscopic Studies on Cyclic Penta- And Hexa-peptides. Detailed Examination of Hydrogen Bonding in Beta- And Gamma-turns Determined by Nmr JF - SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY J2 - SPECTROCHIM ACTA A VL - 54 PY - 1998 IS - 5 SP - 773 EP - 786 PG - 14 SN - 1386-1425 DO - 10.1016/S1386-1425(98)00028-6 UR - https://m2.mtmt.hu/api/publication/1087420 ID - 1087420 N1 - Department of Organic Chemistry, Eötvös Loránd Univ., P.O. Box 32, H-1815 Budapest 112, Hungary Central Pharma Research, Hoechst AG, G 838, D-65926 Frankfurt, Germany Inst. fur Org. Chem. und Biochem., Lehrstuhl II, TU München, Lichtenbergstraße 4, D-85747 Garching, Germany Cited By :29 Export Date: 7 September 2023 CODEN: SAMCA Correspondence Address: Hollósi, M.; Department of Organic Chemistry, P.O. Box 32, H-1815 Budapest 112, Hungary; email: hollosi@ludens.elte.hu AB - A series of eight cyclic penta-and hexapeptides with hydrogen-bonded beta- and gamma-turn structures have been investigated by FTIR and CD spectroscopy. The analysis of the amide I band contour (1700-1600 cm(-1)) by Fourier self-deconvolution and nonlinear curve-fitting shows that infrared spectroscopy is a useful method in detecting H-bonded beta- and gamma-turns. FTIR spectra of the studied peptides were recorded both in TFE and in DMSO. It has been found that well-established beta-turns give rise to characteristic acceptor amide I bands between 1642 and 29 cm(-1), while bands appearing at similar to 1650 cm(-1) and 1625-15 cm(-1) an due to acceptor amide carbonyls of weakly and strongly H-bonded gamma-turns, respectively. The low-frequency component bands are often weaker or missing in the spectra obtained in DMSO, the changes in the relative band intensities can be explained on the basis of the different solvating property of the two solvents. CD spectra obtained in TFE were in general in good agreement with the IR spectroscopic data, indicating a mixture of conformers comprising more or less well defined turns. Previous NMR and MD studies on these cyclic peptides made possible the assignment of acceptor amide I component bands to particular carbonyls involved in intramolecular H-bonds. (C) 1998 Elsevier Science B.V. All rights reserved. LA - English DB - MTMT ER - TY - JOUR AU - Vass, Elemér AU - Holly, Sándor AU - Majer, Zsuzsanna (Deckerné) AU - Samu, J AU - Laczko, I AU - Hollósi, Miklós TI - Ftir And CD Spectroscopic Detection of H-bonded Folded Polypeptide Structures JF - JOURNAL OF MOLECULAR STRUCTURE J2 - J MOL STRUCT VL - 408 PY - 1997 SP - 47 EP - 56 PG - 10 SN - 0022-2860 DO - 10.1016/S0022-2860(96)09493-8 UR - https://m2.mtmt.hu/api/publication/1087414 ID - 1087414 N1 - Department of Organic Chemistry, Eötvös University, P.O.B. 32, H-1518 Budapest 112, Hungary Ctrl. Res. Institute of Chemistry, P.O.B. 17, H-1525 Budapest, Hungary Institute of Biophysics, Biological Research Centre, P.O.B. 521, H-6701 Szeged, Hungary Cited By :12 Export Date: 7 September 2023 CODEN: JMOSB Correspondence Address: Hollosi, M.; Department of Organic Chemistry, P.O.B. 32, H-1518 Budapest 112, Hungary AB - The FTIR spectra of a selection of cyclic and linear peptides were measured in DMSO and TFE, The backbone conformation in DMSO of the cyclic models has been inferred from ROESY-based interproton connectivities and the temperature coefficients of the NH protons. The FTIR measurements give support to the following assignment of low-frequency amide I bands: > 1645 cm(-1), open (weakly H-bonded) beta- and gamma-turns; approximate to 1640 cm(-1), beta-turns (1 <-- 4 H-bonded); approximate to 1625 cm(-1), gamma-turns (1 <-- 3 H-bonded); < 1620 cm(-1), beta- and gamma-turns with bifurcated H-bondings, Solvent-dependence studies on the diamide models Ac-Xxx-NHCH3 (8, Xxx = Pro, Ala and Gly) suggest that it is the inverse gamma-turn (C-7(eq)) structure which is capable of forming a strong 1 <-- 3 intramolecular H-bond (band at approximate to 1625 cm(-1)). DMSO destroys 1 <-- 3 IHBs of gamma-turns and bifurcated turn systems even in cyclic peptides but does not affect 1 <-- 4 IHBs. TFE has a stabilizing effect an both 1 <-- 4 and 1 <-- 3 H-bondings which gives rise to mixtures of beta- and gamma-turn conformers. Contrary to vibrational spectroscopy, circular dichroism can differentiate between type I(III) and type II beta-turns showing class C and class B CD spectra, respectively. Based on the above findings, a class C CD spectrum measured in TFE can reflect the predominance of type I(III) beta-turn conformation, but it may also be a composite of subspectra of H-bonded beta-turn and gamma-turn as well as open conformers. (C) 1997 Elsevier Science B.V. LA - English DB - MTMT ER - TY - JOUR AU - VASS, E AU - Majer, Zsuzsanna (Deckerné) AU - Laczkó, Ilona AU - HOLLOSI, M TI - FTIR and CD spectroscopic detection of H-bonded folded polypeptide structures. JF - JOURNAL OF MOLECULAR STRUCTURE J2 - J MOL STRUCT VL - 4089 PY - 1997 SP - 47 EP - 56 PG - 10 SN - 0022-2860 UR - https://m2.mtmt.hu/api/publication/1907266 ID - 1907266 LA - English DB - MTMT ER -