Sequences of homologous β-lactamases from clinical isolates of Serratia marcescens with different substrate specificities
Sequences of homologous β-lactamases from clinical isolates of Serratia marcescens with different substrate specificities
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DOI：
10.1128/aac.42.1.176
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发表时间：
1998-01-01
影响因子：
4.9
通讯作者：
Mitsuhashi, S
中科院分区：
文献类型：
--
作者：
Matsumura, N;Minami, S;Mitsuhashi, S
对两种第一组β-内酰胺酶SRT-1和SST-1的基因进行了测序。粘质沙雷氏菌临床分离株GN16694和GN19450产β-内酰胺酶。得到的酶有96%的同源性。SRT-1对氧化亚氨基头孢菌素有较强的水解性，而SST-1对头孢菌素几乎没有水解性。在第一组β-内酰胺酶保守的第三基序213位，SRT-1和SST-1分别含有Lys和Glu。通过定点突变，将SST-1第213位的Glu替换为Lys，产生了一种能降解氧化亚氨基头孢菌素的酶。
Genes for two group 1 beta-lactamases, SRT-1 and SST-1, were sequenced. These beta-lactamases were produced by clinical isolates of Serratia marcescens, isolates GN16694 and GN19450, respectively. The resulting enzymes were 96% identical. SRT-1 hydrolyzed oxyimino cephalosporins, but SST-1 hardly hydrolyzed them. At residue 213 in the third motif, which is conserved among group 1 beta-lactamases, SRT-1 and SST-1 had Lys and Glu, respectively. By site-directed mutagenesis, the substitution of Glu by Lys at residue 213 in SST-1 resulted in an enzyme that hydrolyzed oxyimino cephalosporins.