Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published August 8, 1995 | Published
Journal Article Open

Response of Rubredoxin from Pyrococcus furiosus to Environmental Changes: Implications for the Origin of Hyperthermostability

Abstract

The bases of the hyperthermostability of rubredoxin from Pyrococcus furiosus (RdPf) have been probed by structural perturbations induced by solution pH and ionic strength changes. Comparison of the solution behavior at pH 7 and pH 2, as probed by far- and near-UV circular dichroism, Trp fluorescence emission, l-anilinonaphthalene-8-sulfonate (ANS) binding, and NMR spectroscopy, reveals the presence of only minimal structural variations at room temperature. At pH 2, the protein displays a surprising nearly native-like behavior at high ionic strength while, at low ionic strength, it is capable of strongly binding the hydrophobic probe ANS. All the secondary and tertiary structural features, including the environment of the hydrophobic core, appear to be intact regardless of pH and ionic strength. The apparent "melting" or denaturation temperature at pH 2, however, is 42 °C lower than at pH 7. This is attributed to the perturbation of many electrostatic interactions, including the disruption of all the ion pairs, which is complete at pH 2, as indicated by electrometric pH titrations. The implications of these findings for the origins of the hyperthermostability of rubredoxin are discussed.

Additional Information

© 1995 American Chemical Society. This work was supported by NIH Grants GM 22432 (S.I.C.) and GM 50736 (M.W.W.A.) from the National Institute of General Medical Sciences, U.S. Public Health Service. Contribution No. 9039 from the Arthur Amos Noyes Laboratories of Chemical Physics. We thank Professor Pamela J. Bjorkman for the use of the program GRASP and Professor Douglas C. Rees for helpful discussion on this study.

Attached Files

Published - bi00031a007.pdf

Files

bi00031a007.pdf
Files (2.7 MB)
Name Size Download all
md5:a56af90acf2173401cc1b74118518217
2.7 MB Preview Download

Additional details

Created:
August 20, 2023
Modified:
October 17, 2023