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Comparison of distance information in [TOAC 1 , Glu(OMe) 7, 18, 19 ] alamethicin F50/5 from paramagnetic relaxation enhancement measurements with data obtained from an X‐ray diffraction‐based model
Author(s) -
Jose Rani Alphonsa,
De Zotti Marta,
Peggion Cristina,
Formaggio Fernando,
Toniolo Claudio,
De Borggraeve Wim M.
Publication year - 2011
Publication title -
journal of peptide science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 66
eISSN - 1099-1387
pISSN - 1075-2617
DOI - 10.1002/psc.1354
Subject(s) - chemistry , alamethicin , nitroxide mediated radical polymerization , peptide , amino acid , crystallography , relaxation (psychology) , population , x ray , stereochemistry , membrane , physics , organic chemistry , biochemistry , polymer , lipid bilayer , quantum mechanics , psychology , social psychology , demography , radical polymerization , sociology , copolymer
Abstract Peptaibol antibiotics are membrane‐active linear peptides of fungal origin that are characterized by a high population of the C α ‐tetrasubstituted, strongly helicogenic, α‐amino acid, α‐aminoisobutyric acid, an N ‐terminal acetyl group, and a C ‐terminal 1,2‐amino alcohol. Alamethicins (Alms), among the longest peptaibiotics, are a group of closely sequence‐related peptides composed of 19 amino acid residues. [TOAC 1 , Glu(OMe) 7, 18, 19 ] Alm and [TOAC 16 , Glu(OMe) 7, 18, 19 ] Alm are synthetic, nitroxide free‐radical labeled analogs of [Glu(OMe) 7, 18, 19 ] Alm F50/5. In this work, nitroxide to peptide NH proton distance information obtained from paramagnetic relaxation enhancement (PRE) studies on [TOAC 1 , Glu(OMe) 7, 18, 19 ] Alm is compared with distances derived from an X‐ray diffraction‐based model. The methodology for PRE determination, as well as the generation of the X‐ray diffraction‐based model three‐dimensional structures, is discussed. The distances obtained from PRE measurements are in close agreement with the information derived from the X‐ray diffraction‐based model. This finding suggests that this type of information could be implemented as long‐range distance restraints in NMR‐based structure determination. Copyright © 2011 European Peptide Society and John Wiley & Sons, Ltd.