해양미생물로부터 유래한 광학특이성 lipase를 이용한 Levofloxacin의 생성

Abstract

Levofloxacin, (S)-isomer of the (R),(S)-ofloxacin, is a new fluoroquinolone antibiotic. To screen strains producing a lipase that hydrolyzes the (R),(S)-ofloxacin ester to levofloxacin, 151 isolates showing lipolytic activity on tributyrin agar plate were tested for the hydrolysis of ofloxacin ester. 3 strains among them were selected, and one of them, identified as the yeast Yarrowia lipolytica CL180, was found to enantioselectively hydrolyze the (S)-enantiomer of the (R),(S)-ofloxacin ester. The enantioselective lipase-encoding gene was cloned by screening genomic library of Y. lipolytica CL 180 and the sequence was determined. The lipase gene consisted of 1431-bp nucleotides, encoding a polypeptide of 476 amino acids with a molecular mass of 52 kDa. The consensus sequence G-X1-S-X2-G in most serine lipases was well conserved. The catalytic apparatus involving the triad serine, aspartate, and histidine was also found in the protein sequence. The amino acids comparison showed a high similarity with the yeast lipases of type B1 carboxylesterase/lipase family.