Skip Navigation


PEDS Advance Access originally published online on March 29, 2004
Protein Engineering Design and Selection 2004 17(3):285-291; doi:10.1093/protein/gzh027
This Article
Right arrow Full Text Freely available
Right arrow FREE Full Text (PDF) Freely available
Right arrow All Versions of this Article:
17/3/285    most recent
gzh027v1
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in ISI Web of Science
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Add to My Personal Archive
Right arrow Download to citation manager
Right arrow Search for citing articles in:
ISI Web of Science (2)
Right arrowRequest Permissions
Google Scholar
Right arrow Articles by Simler, B.R.
Right arrow Articles by Matthews, C.R.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Simler, B.R.
Right arrow Articles by Matthews, C.R.
Social Bookmarking
Add to CiteULike   Add to Connotea   Add to Del.icio.us  
What's this?

© 2004 Oxford University Press

Zinc binding drives the folding and association of the homo-trimeric {gamma}-carbonic anhydrase from Methanosarcina thermophila

B.Robert Simler1, Brandon L. Doyle2,3 and C.Robert Matthews1,4

1Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, 364 Plantation Street, Worcester, MA 01605 and 2Department of Chemistry and Center for Biomolecular Structure and Function, The Pennsylvania State University, University Park, PA 16802, USA 3Present address: Eli Lilly and Company, Indianapolis, IN 46285, USA

4 To whom correspondence should be addressed. e-mail: c.robert.matthews{at}umassmed.edu

Carbonic anhydrase from the archeon Methanosarcina thermophila (Cam) is a homo-trimeric enzyme, the left-handed ß-helical subunits of which bind three catalytic Zn2+ ions at symmetry-related subunit interfaces. The observation of activity for holo-Cam at nanomolar concentrations provides a minimal estimated free energy of folding and assembly of the trimeric holo-complex of ~70 kcal (mol trimer)–1 at standard state. Although the direct measurement of stability by chemical denaturation was precluded by the irreversible unfolding of the holo-enzyme, the reversible unfolding of metal-free apo-Cam is well described by a three-state model involving the folded apo-trimer, the folded monomer and the unfolded monomer. The monomer is estimated to have a stability of 4.0 ± 0.3 kcal (mol monomer)–1. The association to form apo-trimer contributes 13.2 ± 0.4 kcal (mol trimer)–1, a value confirmed by analytical ultracentrifugation measurements. Far- and near-UV circular dichroism data show a progressive increase in secondary and tertiary structure as the apo-monomer is converted to holo-trimer. The literature value for the free energy of binding of one Zn2+ ion to a canonical active site, 16.4 kcal mol–1, is consistent with the presumption that the >45 kcal (mol trimer)–1 generated by the binding of three ions represents the major contribution to the stability of the holo-trimeric Cam.

Received March 2, 2004; accepted March 4, 2004 Edited by Lynne Regan


Add to CiteULike CiteULike   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us    What's this?


This article has been cited by other articles:


Home page
 J. Bacteriol.Home page
S. S.-W. Cot, A. K.-C. So, and G. S. Espie
A Multiprotein Bicarbonate Dehydration Complex Essential to Carboxysome Function in Cyanobacteria
J. Bacteriol., February 1, 2008; 190(3): 936 - 945.
[Abstract] [Full Text] [PDF]


Disclaimer: Please note that abstracts for content published before 1996 were created through digital scanning and may therefore not exactly replicate the text of the original print issues. All efforts have been made to ensure accuracy, but the Publisher will not be held responsible for any remaining inaccuracies. If you require any further clarification, please contact our Customer Services Department.