Open AccessComparative studies of conformation and internal mobility in native and circular basic pancreatic trypsin inhibitor by 1 H nuclear magnetic resonance in solution
Author(s) -
CHAZIN Walter J.,
GOLDENBERG David P.,
CREIGHTON Thomas E.,
WÜTHRICH Kurt
Publication year - 1985
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1985.tb09215.x
Subject(s) - salt bridge , chemistry , chemical shift , nuclear overhauser effect , amide , peptide bond , covalent bond , crystallography , intramolecular force , nuclear magnetic resonance spectroscopy , proton , two dimensional nuclear magnetic resonance spectroscopy , native state , resonance (particle physics) , trypsin , nuclear magnetic resonance , stereochemistry , peptide , biochemistry , enzyme , physics , organic chemistry , particle physics , quantum mechanics , mutant , gene
A circular derivative of bovine pancreatic trypsin inhibitor (c‐BPTI) with the C‐ and N‐termini covalently linked with a peptide bond, has been studied in solution by spectroscopic techniques, principally two‐dimensional 1 H NMR. Near complete sequence specific assignment of the 1 H NMR spectrum of c‐BPTI has been obtained in a highly efficient manner, using recently developed experimental techniques. The assignments serve as the necessary background for detailed examination of the effects of the chemical modification on global and local features of the protein conformation and on the internal mobility. Analysis of chemical shifts, spin‐spin coupling constants, amide proton exchange and proton‐proton Overhauser enhancements indicates that perturbations of the native BPTI conformation in c‐BPTI involve exclusively residues adjacent to the modification site. The strict localization and small magnitude of the conformation changes relative to native BPTI emphasize the important role of the salt bridge between the chain ends in determining the solution conformation and dynamics in the chain terminal regions of the native protein.