earticle

영어

β-Lactam antibiotics such as penicillins and cephalosporins have a four-atomring as a common element in their structure. The β- lactamases, which catalyze the inactivation of these ntibiotics, are of great interest because of their high incidence in pathogenic bacteria. A novel oligomeric class C β-lactamase (Est-Y29) from a metagenomic library was expressed, purified and crystallized. Est-Y29 possesses the Ser-X-X-Lys motif which is highly conserved among β-lactamases and site-directed mutagenesis of Ser to Ala resulted in complete loss of activity(1). To our knowledge, Est-Y29 is the first multimeric class C β-lactamase with broad hydrolytic activity. The recombinant protein was expressed in Escherichia coli with an N-terminal 6×His tag and purified to homogeneity. EstY-29 was crystallized and X-ray intensity data were collected to 1.49 A ° resolution using synchrotron radiation. The crystal structure of Est-Y29 will provide an invaluable framework for understanding its unique features such as its oligomeric state, high stability and (S)-specific stereoselectivity, as well as its significance for the development of antibiotic drugs against class C β-lactamases.