Detection of residue contacts in a protein folding intermediate.
Protein folding can be described in terms of the development of specific contacts between residues as a highly disordered polypeptide chain converts into the native state. Here we describe an NMR based strategy designed to detect such contacts by observation of nuclear Overhauser effects (NOEs). Experiments with alpha-lactalbumin reveal the existence of extensive NOEs between aromatic and aliphatic protons in the archetypal molten globule formed by this protein at low pH. Analysis of their time development provides direct evidence for near-native compactness of this state. Through a rapid refolding procedure the NOE intensity can be transferred efficiently into the resolved and assigned spectrum of the native state. This demonstrates the viability of using this approach to map out time-averaged interactions between residues in a partially folded protein.
Balbach
J
J
Oxford Centre for Molecular Sciences, New Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QT, United Kingdom.
Forge
V
V
Lau
W S
WS
Jones
J A
JA
van Nuland
N A
NA
Dobson
C M
CM
D000818:Animals; D002417:Cattle; D007768:Lactalbumin / Q000737:chemistry*; D017510:Protein Folding
D007768:Lactalbumin