Gt. Howard et al., Cloning, nucleotide sequencing and characterization of a polyurethanase gene (pueB) from Pseudomonas chlororaphis, INT BIO BIO, 47(3), 2001, pp. 141-149
A second gene (pueB, polyurethane esterase B) encoding an extracellular pol
yurethanase (PueB) was cloned from Pseudomonas chlororaphis into Escherichi
a coli. The recombinant polyurethanase showed esterase activity when assaye
d with various p-nitrophenyl substrates and lipase activity when assayed wi
th triolein. Nucleotide sequencing of pueB showed an open reading frame of
1695 bp encoding a 60-kDa protein of 565 amino acid residues, with the seri
ne hydrolase consensus sequence GXSXG and a C-terminal secretion signal (G-
G-X-G-X-D-X-X-X). Unlike the PueA polyurethanase, PueB contains a putative
N-terminal signal peptide. Comparison between the amino acid and nucleotide
sequences of these two genes revealed that they share 42% and 59% identity
respectfully. Parsimony analysis of the predicted amino acid sequences for
the PueB. PueA, and other polyurethanase enzymes and similar lipase enzyme
s was performed. Interestingly the polyurethanase enzymes do not form a sin
gle cluster, but appear to be distributed among multiple lineages. These an
alyses suggest that the polyurethanase enzymes thus far studied have evolve
d from lipases, and are not derived from a single source. (C) 2001 Elsevier
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