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1 H‐nmr parameters of the common amino acid residues measured in aqueous solutions of the linear tetrapeptides H‐Gly‐Gly‐ X ‐ L ‐Ala‐OH
Author(s) -
Bundi Arno,
Wüthrich Kurt
Publication year - 1979
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.1979.360180206
Subject(s) - chemistry , aqueous solution , random coil , titration , chemical shift , crystallography , amino acid , stereochemistry , analytical chemistry (journal) , circular dichroism , organic chemistry , biochemistry
The 1 H‐nmr chemical shifts and the spin–spin coupling constants of the common amino acid residues were measured in solutions of the linear tetrapeptides H‐Gly‐Gly‐ X ‐ L ‐Ala‐OH in D 2 O and H 2 O, the influence of X on the nmr parameters of the neighboring residues Gly 2 and Ala 4 was investigated. The titration parameters for the side chains of Asp, Glu, Lys, Tyr, and His were determined. The p K a values obtained in D 2 O, with the use of pH‐meter readings with a combination glass electrode uncorrected for istope effects, were 0.06 pH units higher in the acidic range and 0.10 pH units higher in the basic range than the corresponding p K a values in H 2 O. This suggests that the present data are suitable “random‐coil” 1 H‐nmr parameters for conformational studies of polypeptide chains in D 2 O and H 2 O solutions.