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A sequence‐dependent 1 H‐NMR study on the formation of β‐turns in tetrapeptides containing charged residues
Author(s) -
Liu Xiaohong,
Scott Paul G.,
Otter Albin,
Kotovych George
Publication year - 1992
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.360320203
Subject(s) - tetrapeptide , chemistry , side chain , salt bridge , residue (chemistry) , turn (biochemistry) , stereochemistry , population , peptide , organic chemistry , biochemistry , mutant , gene , polymer , demography , sociology
The importance of side‐chain charge interactions in the formation of β‐turns was studied. Sixteen protected NAc‐tetrapeptide amides were studied, namely the variants of DEKS: NEKS, EEKS, DDKS, DQKS, NQKS, DERS, NERS, EERS, DDRS, NDRS, DQRS, and DKES. Three tetrapeptides—NPDM, NSDM, and NDDS—were also studied as they have a high probability of forming β‐turns, based on statistical predictions. The results indicate that a small proportion of type I β‐turn exists in solutions of DEKS and DERS in methanol/ water (60/40), while NEKS has an even smaller population of this turn. The other tetrapeptides are present in solution only in the extended conformation. These results clearly show the importance of the salt bridge between the side chains of K 2 and E 3 or R 2 and E 3 , as well as the importance of the charge on the side chain of the first residue in stabilizing the β‐turn. The relevance of statistical predictions for β‐turns in short peptides is discussed.