HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Robic, S. Articles by Marqusee, S. Search for Related Content PubMed PubMed Citation Articles by Robic, S. Articles by Marqusee, S. Social Bookmarking                   What's this?

Contributions of folding cores to the thermostabilities of two ribonucleases H

Department of Molecular and Cell Biology, University of California, Berkeley, California 94720, USA

Reprint request to: Susan Marqusee, Department of Molecular and Cell Biology, University of California, 229 Stanley Hall, Berkeley, CA 94720, USA; e-mail: marqusee{at}uclink4.berkeley.edu; fax: (510) 643-9290.

To investigate the contribution of the folding cores to the thermodynamic stability of RNases H, we used rational design to create two chimeras composed of parts of a thermophilic and a mesophilic RNase H. Each chimera combines the folding core from one parent protein and the remaining parts of the other. Both chimeras form active, well-folded RNases H. Stability curves, based on CD-monitored chemical denaturations, show that the chimera with the thermophilic core is more stable, has a higher midpoint of thermal denaturation, and a lower change in heat capacity (Cp) upon unfolding than the chimera with the mesophilic core. A possible explanation for the low Cp of both the parent thermophilic RNase H and the chimera with the thermophilic core is the residual structure in the denatured state. On the basis of the studied parameters, the chimera with the thermophilic core resembles a true thermophilic protein. Our results suggest that the folding core plays an essential role in conferring thermodynamic parameters to RNases H.

Keywords: Thermodynamic stability of proteins; chimera; stability curves; heat capacity; folding core; ribonuclease H

CiteULike    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

				S. Robic, M. Guzman-Casado, J. M. Sanchez-Ruiz, and S. Marqusee Role of residual structure in the unfolded state of a thermophilic protein PNAS, September 30, 2003; 100(20): 11345 - 11349. [Abstract] [Full Text] [PDF]

				A. Mozo-Villarias, J. Cedano, and E. Querol A simple electrostatic criterion for predicting the thermal stability of proteins Protein Eng. Des. Sel., April 1, 2003; 16(4): 279 - 286. [Abstract] [Full Text] [PDF]

				H.-X. Zhou Toward the Physical Basis of Thermophilic Proteins: Linking of Enriched Polar Interactions and Reduced Heat Capacity of Unfolding Biophys. J., December 1, 2002; 83(6): 3126 - 3133. [Abstract] [Full Text] [PDF]