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Thermodynamic characterizations of an intramolecularly hydrogen bonded C 5 ‐structure across proteinogenic residue
Author(s) -
Ashish ,
Kishore R
Publication year - 1997
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(97)01239-8
Subject(s) - chemistry , residue (chemistry) , hydrogen , hydrogen bond , stereochemistry , crystallography , molecule , organic chemistry
Thermodynamic investigations of a smallest possible intramolecularly hydrogen bonded C 5 ‐structure, across a Thr residue, in model peptides Boc‐Xxx‐Thr‐NH 2 (Xxx=Ile, 1 or Leu, 2), indicated unusual thermal stability of the structure in non‐polar medium. An analysis of van't Hoff plots, constructed from variable temperature 1 H NMR data, yielded the thermodynamic parameters of a hydrogen bonded five‐membered ring. The non‐significance of the spatial organizations of the preceding C δ H 3 bearing hydrophobic proteinogenic residue on the thermal stability of the C 5 ‐structure has been observed. The results revealed that the contribution of this element of secondary structure is quantifiable and the stability appeared to be roughly comparable to other intramolecularly hydrogen bonded reverse turn structures frequently observed in polypeptides and proteins.