Proline isomerism leads to multiple folded conformations of calbindin D sub 9k : Direct evidence from two-dimensional sup 1 H NMR spectroscopy

Journal Article · Sat Apr 01 04:00:00 EST 1989 · Proceedings of the National Academy of Sciences of the United States of America; (USA)

DOI:https://doi.org/10.1073/pnas.86.7.2195· OSTI ID:5158655

Chazin, W J; Koerdel, J; Drakenberg, T; Thulin, E; Brodin, P; Grundstroem, T; Forsen, S ^[1]

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1. Research Institute of Scripps Clinic, La Jolla, CA (USA)

A complete analysis of calbindin D{sub 9k} by two-dimensional {sup 1}H nuclear magnetic resonance spectroscopy has established the existence of two conformations for the folded protein in solution. Well-resolved major and minor resonances in a ratio of 3:1 are observed throughout the {sup 1}H NMR spectrum. Two-dimensional exchange experiments show that the major and minor species are related by an equilibrium process. Analysis of short proton-proton distances along the peptide backbone, identified by two-dimensional nuclear Overhauser effect spectroscopy, provides unambiguous evidence that the two forms of the folded protein differ only in the isomerization state of the peptide bond between Gly-42 and Pro-43. Cis-trans isomerism of Pro-43 is thereby directly identified as the cause of multiple conformations for the folded protein in solution. In addition, when Pro-43 is mutated to a glycine residue there is no indication of multiple conformations. These results provide evidence for the possibility of conformational heterogeneity in the native state of globular proteins.

• OSTI ID: 5158655
• Journal Information: Proceedings of the National Academy of Sciences of the United States of America; (USA), Journal Name: Proceedings of the National Academy of Sciences of the United States of America; (USA) Vol. 86:7; ISSN 0027-8424; ISSN PNASA
• Country of Publication: United States
• Language: English

Related Subjects

550601* -- Medicine-- Unsealed Radionuclides in Diagnostics
62 RADIOLOGY AND NUCLEAR MEDICINE
ALKALINE EARTH METAL COMPOUNDS
AMINES
AMINO ACIDS
AQUEOUS SOLUTIONS
AZOLES
BARYONS
CALCIUM COMPOUNDS
CARBOXYLIC ACIDS
CHEMICAL REACTIONS
DISPERSIONS
ELEMENTARY PARTICLES
FERMIONS
GLYCINE
HADRONS
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
ISOMERIZATION
MAGNETIC RESONANCE
MEMBRANE PROTEINS
MEMBRANES
MIXTURES
NUCLEAR MAGNETIC RESONANCE
NUCLEONS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
OVERHAUSER EFFECT
PROLINE
PROTEINS
PROTONS
PYRROLES
PYRROLIDINES
RESONANCE
SOLUTIONS