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The effects of alpha‐helix on the stability of Asn residues: Deamidation rates in peptides of varying helicity
Author(s) -
Kosky Andrew A.,
Razzaq Ursula O.,
Treuheit Michael J.,
Brems David N.
Publication year - 1999
Publication title -
protein science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.353
H-Index - 175
eISSN - 1469-896X
pISSN - 0961-8368
DOI - 10.1110/ps.8.11.2519
Subject(s) - deamidation , circular dichroism , helicity , chemistry , peptide , conformational isomerism , alpha (finance) , crystallography , stereochemistry , biochemistry , organic chemistry , physics , molecule , enzyme , particle physics , medicine , construct validity , nursing , patient satisfaction
Asn deamidation was monitored in Ala‐based octadecapeptides of varying α‐helicity. Gly was substituted for Ala residues at positions 6 and 16 to create a peptide with less helicity. Ala → Gly substitutions were made at three or more residues from the Asn to negate known primary sequence effects on deamidation rates. The extent of helicity and rate of Asn deamidation for alkaline aqueous solutions of each peptide was measured as a function of temperature by circular dichroism and reversed‐phase high‐performance liquid chromatography, respectively. The rate of deamidation in the peptides was inversely proportional to the extent of α‐helicity. The results support the conclusion that Asn deamidation only occurs in the nonhelical population of conformers.