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 Ababou, A. Articles by Desjarlais, J. R. Search for Related Content PubMed PubMed Citation Articles by Ababou, A. Articles by Desjarlais, J. R. Social Bookmarking                   What's this?

Solvation energetics and conformational change in EF-hand proteins

Department of Chemistry, Pennsylvania State University, University Park, Pennsylvania 16802, USA

Reprint requests to: John R. Desjarlais, 408 Chandlee Laboratory, Department of Chemistry, University Park, PA 16802, USA; e-mail: jrd{at}chem.psu.edu; fax: (814) 863-8403.

Calmodulin and other members of the EF-hand protein family are known to undergo major changes in conformation upon binding Ca²⁺. However, some EF-hand proteins, such as calbindin D9k, bind Ca²⁺ without a significant change in conformation. Here, we show the importance of a precise balance of solvation energetics to conformational change, using mutational analysis of partially buried polar groups in the N-terminal domain of calmodulin (N-cam). Several variants were characterized using fluorescence, circular dichroism, and NMR spectroscopy. Strikingly, the replacement of polar side chains glutamine and lysine at positions 41 and 75 with nonpolar side chains leads to dramatic enhancement of the stability of the Ca²⁺-free state, a corresponding decrease in Ca²⁺-binding affinity, and an apparent loss of ability to change conformation to the open form. The results suggest a paradigm for conformational change in which energetic strain is accumulated in one state in order to modulate the energetics of change to the alternative state.

Keywords: Conformational change; EF-hand; calmodulin; calbindin; solvation; buried polar; calcium

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

This article has been cited by other articles:

				S. O. Yesylevskyy, V. N. Kharkyanen, and A. P. Demchenko The Change of Protein Intradomain Mobility on Ligand Binding: Is It a Commonly Observed Phenomenon? Biophys. J., October 15, 2006; 91(8): 3002 - 3013. [Abstract] [Full Text] [PDF]

				S. B. Tikunova and J. P. Davis Designing Calcium-sensitizing Mutations in the Regulatory Domain of Cardiac Troponin C J. Biol. Chem., August 20, 2004; 279(34): 35341 - 35352. [Abstract] [Full Text] [PDF]

				M. S. Yousef, W. A. Baase, and B. W. Matthews Use of sequence duplication to engineer a ligand-triggered, long-distance molecular switch in T4 lysozyme PNAS, August 10, 2004; 101(32): 11583 - 11586. [Abstract] [Full Text] [PDF]

				C. M. Shepherd and H. J. Vogel A Molecular Dynamics Study of Ca2+-Calmodulin: Evidence of Interdomain Coupling and Structural Collapse on the Nanosecond Timescale Biophys. J., August 1, 2004; 87(2): 780 - 791. [Abstract] [Full Text] [PDF]

				N. Pokala and T. M. Handel Energy functions for protein design I: Efficient and accurate continuum electrostatics and solvation Protein Sci., April 1, 2004; 13(4): 925 - 936. [Abstract] [Full Text] [PDF]

				D. M. Casey, T. Yagi, R. Kamiya, and G. B. Witman DC3, the Smallest Subunit of the Chlamydomonas Flagellar Outer Dynein Arm-docking Complex, Is a Redox-sensitive Calcium-binding Protein J. Biol. Chem., October 24, 2003; 278(43): 42652 - 42659. [Abstract] [Full Text] [PDF]

				Y. Ye, S. Shealy, H.-W. Lee, I. Torshin, R. Harrison, and J. J. Yang A grafting approach to obtain site-specific metal-binding properties of EF-hand proteins Protein Eng. Des. Sel., June 1, 2003; 16(6): 429 - 434. [Abstract] [Full Text] [PDF]

				W. S. VanScyoc, B. R. Sorensen, E. Rusinova, W. R. Laws, J. B. A. Ross, and M. A. Shea Calcium Binding to Calmodulin Mutants Monitored by Domain-Specific Intrinsic Phenylalanine and Tyrosine Fluorescence Biophys. J., November 1, 2002; 83(5): 2767 - 2780. [Abstract] [Full Text] [PDF]

				A. V. Gribenko, M. Guzman-Casado, M. M. Lopez, and G. I. Makhatadze Conformational and thermodynamic properties of peptide binding to the human S100P protein Protein Sci., June 1, 2002; 11(6): 1367 - 1375. [Abstract] [Full Text] [PDF]

				M. R. Nelson, E. Thulin, P. A. Fagan, S. Forsen, and W. J. Chazin The EF-hand domain: A globally cooperative structural unit Protein Sci., February 1, 2002; 11(2): 198 - 205. [Abstract] [Full Text] [PDF]

				W. S. Vanscyoc and M. A. Shea Phenylalanine fluorescence studies of calcium binding to N-domain fragments of Paramecium calmodulin mutants show increased calcium affinity correlates with increased disorder Protein Sci., September 1, 2001; 10(9): 1758 - 1768. [Abstract] [Full Text] [PDF]