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

J. Biol. Chem., Vol. 280, Issue 29, 26997-27003, July 22, 2005

This Article Full Text Full Text (PDF) All Versions of this Article: 280/29/26997    most recent M502678200v1 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 Mengwasser, K. E. Articles by Di Cera, E. Search for Related Content PubMed PubMed Citation Articles by Mengwasser, K. E. Articles by Di Cera, E. Social Bookmarking                      What's this?

Hirudin Binding Reveals Key Determinants of Thrombin Allostery^*

Kristen E. Mengwasser, Leslie A. Bush, Peter Shih, Angelene M. Cantwell, and Enrico Di Cera

From the Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri 63110

Thrombin exists in two allosteric forms, slow (S) and fast (F), that recognize natural substrates and inhibitors with significantly different affinities. Because under physiologic conditions the two forms are almost equally populated, investigation of thrombin function must address the contribution from the S and F forms and the molecular origin of their differential recognition of ligands. Using a panel of 79 Ala mutants, we have mapped for the first time the epitopes of thrombin recognizing a macromolecular ligand, hirudin, in the S and F forms. Hirudin binding is a relevant model for the interaction of thrombin with fibrinogen and PAR1 and is likewise influenced by the allosteric SF transition. The epitopes are nearly identical and encompass two hot spots, one in exosite I and the other in the Na⁺ site at the opposite end of the protein. The higher affinity of the F form is due to the preferential interaction of hirudin with Lys-36, Leu-65, Thr-74, and Arg-75 in exosite I; Gly-193 in the oxyanion hole; and Asp-221 and Asp-222 in the Na⁺ site. Remarkably, no correlation is found between the energetic and structural involvements of thrombin residues in hirudin recognition, which invites caution in the analysis of protein-protein interactions in general.

Received for publication, March 10, 2005 , and in revised form, May 26, 2005.

^* This work was supported in part by National Institutes of Health Research Grants HL49413, HL58141, and HL73813. The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

To whom correspondence should be addressed: Dept. of Biochemistry and Molecular Biophysics, Washington University School of Medicine, Box 8231, St. Louis, MO 63110. Tel.: 314-362-4185; Fax: 314-747-5354; E-mail: enrico{at}wustl.edu.

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

This article has been cited by other articles:

				P. Zania, M. Papaconstantinou, C. S. Flordellis, M. E. Maragoudakis, and N. E. Tsopanoglou Thrombin mediates mitogenesis and survival of human endothelial cells through distinct mechanisms Am J Physiol Cell Physiol, May 1, 2008; 294(5): C1215 - C1226. [Abstract] [Full Text] [PDF]

				C. A. Kretz, A. R. Stafford, J. C. Fredenburgh, and J. I. Weitz HD1, a Thrombin-directed Aptamer, Binds Exosite 1 on Prothrombin with High Affinity and Inhibits Its Activation by Prothrombinase J. Biol. Chem., December 8, 2006; 281(49): 37477 - 37485. [Abstract] [Full Text] [PDF]

				M. E. Papaconstantinou, C. J. Carrell, A. O. Pineda, K. M. Bobofchak, F. S. Mathews, C. S. Flordellis, M. E. Maragoudakis, N. E. Tsopanoglou, and E. Di Cera Thrombin Functions through Its RGD Sequence in a Non-canonical Conformation J. Biol. Chem., August 19, 2005; 280(33): 29393 - 29396. [Abstract] [Full Text] [PDF]