Differences in hydrogen exchange behavior between the oxidized and reduced forms of Escherichia coli thioredoxin.

Publication Type	Academic Article
Authors	Kaminsky S, Richards F
Journal	Protein Sci
Volume	1
Issue	1
Pagination	10-21
Date Published	01/01/1992
ISSN	0961-8368
Keywords	Escherichia coli, Thioredoxins
Abstract	Amide proton exchange of thioredoxin is used to monitor the structural effects of reduction of its single disulfide. An effective 3-5-proton difference between the oxidized and reduced protein form is observed early in proton out-exchange of the whole protein, which is independent of temperature in the range of 5-45 degrees C, indicating that redox-sensitive changes are probably not due to low-energy structural fluctuations. Medium resolution hydrogen exchange experiments have localized the redox-sensitive amide protons to two parts of the sequence that are distant from each other in the three-dimensional structure: the active-site turn and the first beta-strand. The sum of the proton differences observed in the peptides from these regions is equal to that of the whole protein, indicating that all redox-sensitive hydrogen exchange effects are observed in the peptide experiments. A model combining structural changes within the protein matrix with changes in the surface hydration properties is proposed as a mechanism for the communication between distant sites within the protein. Sound velocity and density measurements of reduced and oxidized thioredoxin are presented in the accompanying paper (Kaminsky, S.M. & Richards, F.M., 1992, Protein Sci. 1, 22-30).
DOI	10.1002/pro.5560010103
PubMed ID	1339022
PubMed Central ID	PMC2142074