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Appl. Environ. Microbiol., 07 1995, 2674-2680, Vol 61, No. 7
X Li, S Tetling, UK Winkler, KE Jaeger and MJ Benedik
The gene encoding extracellular lipase of Serratia marcescens has been
identified from a phage lambda genomic library. Formation of orange-red
fluorescent plaques on rhodamine B-triolein plates was used to identify
phages carrying the lipase gene. A 2.8-kb SalI fragment was subcloned into
a plasmid, and lipase was expressed in Escherichia coli. Extracellular
lipase was detected in the presence of the secretion plasmid pGSD6 carrying
the genes prtD, -E, and -F, which guide the secretion of protease from
Erwinia chrysanthemi. Determination of the nucleotide sequence of the
entire cloned fragment revealed an open reading frame coding for a
613-amino-acid protein with a predicted M(r) of 64,800. Analysis of the
amino acid sequence revealed significant homology (around 70%) to lipases
of Pseudomonas fluorescens strains. The lipase-specific consensus sequence
G-X1-S-X2-G resided in the amino- terminal part of the protein, and
carboxyl-terminal consensus sequences were an L-X-G-G-B-G-B-B-X repeat
motif and a so-called aspartate box, respectively, which are both found in
proteins secreted by the class I secretion pathway. Lipase was purified
from the supernatant of a culture carrying a lipase expression vector, and
analysis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis
revealed an M(r) of 64,000 for the purified protein. Our results suggest
that the lipase of S. marcescens belongs to the group of extracellular
enzyme proteins secreted by the class I secretion pathway.
Copyright © 1995, American Society for Microbiology
Gene cloning, sequence analysis, purification, and secretion by Escherichia coli of an extracellular lipase from Serratia marcescens
Department of Biochemical and Biophysical Sciences, University of Houston, Texas 77204-5934, USA.
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