Crystal structure of a cold-adapted class C β-lactamase

Authors


  • Database
    The protein sequence has been deposited in the UniProt Knowledgebase (P85302) with Protein Identification Resource, National Biomedical Research Foundation, Georgetown University Medical Center, Washington, DC 20007

  • The atomic coordinates and structure factors have been deposited in the Protein Data Bank, Research Collaboratory for Structural Bioinformatics, Rutgers University, New Brunswick, NJ, under the code 2QZ6 (http://www.rcsb.org/)

C. Michaux, Chimie Biologique Structurale Laboratory, CPTS group, FUNDP, 61 rue de Bruxelles, B-5000 Namur, Belgium
Fax: +32 81725466
Tel: +32 81725457
E-mail: catherine.michaux@fundp.ac.be

Abstract

In this study, the crystal structure of a class C β-lactamase from a psychrophilic organism, Pseudomonas fluorescens, has been refined to 2.2 Å resolution. It is one of the few solved crystal structures of psychrophilic proteins. The structure was compared with those of homologous mesophilic enzymes and of another, modeled, psychrophilic protein. The elucidation of the 3D structure of this enzyme provides additional insights into the features involved in cold adaptation. Structure comparison of the psychrophilic and mesophilic β-lactamases shows that electrostatics seems to play a major role in low-temperature adaptation, with a lower total number of ionic interactions for cold enzymes. The psychrophilic enzymes are also characterized by a decreased number of hydrogen bonds, a lower content of prolines, and a lower percentage of arginines in comparison with lysines. All these features make the structure more flexible so that the enzyme can behave as an efficient catalyst at low temperatures.

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