title: Primary structure effects on peptide group hydrogen exchange.
abstract: The rate of exchange of peptide group NH hydrogens with the hydrogens of aqueous solvent is sensitive to neighboring side chains. To evaluate the effects of protein side chains, all 20 naturally occurring amino acids were studied using dipeptide models. Both inductive and steric blocking effects are apparent. The additivity of nearest-neighbor blocking and inductive effects was tested in oligo- and polypeptides and, surprisingly, confirmed. Reference rates for alanine-containing peptides were determined and effects of temperature considered. These results provide the information necessary to evaluate measured protein NH to ND exchange rates by comparing them with rates to be expected for the same amino acid sequence is unstructured oligo- and polypeptides. The application of this approach to protein studies is discussed.
authors.affiliation: Johnson Research Foundation, Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia 19104-6059.
authors.forename: Y
authors.initials: Y
authors.lastname: Bai
authors.forename: J S
authors.initials: JS
authors.lastname: Milne
authors.forename: L
authors.initials: L
authors.lastname: Mayne
authors.forename: S W
authors.initials: SW
authors.lastname: Englander
mesh_terms: D000409:Alanine / Q000502:physiology; D000595:Amino Acid Sequence; D002384:Catalysis; D006859:Hydrogen / Q000737:chemistry*; D007700:Kinetics; D008956:Models, Chemical; D010455:Peptides / Q000737:chemistry* / Q000502:physiology; D013329:Structure-Activity Relationship; D013696:Temperature; D014867:Water / Q000737:chemistry
chemical_list: D010455:Peptides; D014867:Water; D006859:Hydrogen; D000409:Alanine