Combinatorial biochemistry and shuffling TEM, SHV and Streptomyces albus omega loops in PSE-4 class A beta-lactamase

The class A PSE-4 beta-lactamase was used for studying the importance of am ino acids in the omega (Omega) loop and its interactions for hydrolysis of beta-lactam antibiotics. By cassette mutagenesis, we replaced the amino aci ds 163-179 Omega loop in PSE-4 with TEM-1, SHV-1 and Streptomyces albus G b eta-lactamase Omega loops. Phenotypic analysis of Escherichia coli recombin ants expressing the Omega loop PSE-4 mutant enzymes gave MICs and kinetic d ata similar to those of wild-type PSE-4.