estA, a gene coding for a cell-bound esterase from Paenibacillus sp. BP-23, is a new member of the bacterial subclass of type B carboxylesterases.
Screening of a gene library from Paenibacillus sp. BP-23 generated in Escherichia coli led to identification of a clone that directed the production of lipolytic activity. From the sequencing data, we found an open reading frame encoding a protein of 485 amino acids with an estimated molecular mass of 53 kDa and a pI of 5.1. Absence of a signal peptide indicated that it was a cell-bound protein. Sequence analysis showed that the protein contained the signature G-XI-S-X2-G included in most serine-esterases and lipases. The cloned protein showed high homology with enzymes belonging to the bacterial subclass of type B carboxylesterases. The enzyme had a significant preference for esters of short-chain fatty acids and showed the kinetics behaviour of a true esterase. Maximum activity was found at pH 7.5 and 37 degrees C, although the enzyme was active in the pH range 6.0- 9.0 and at temperatures up to 45 degrees C. As expected for a serine-esterase, activity was inhibited by phenylmethylsulphonyl fluoride.
Prim
N
N
Department of Microbiology, Faculty of Biology, University of Barcelona, Spain.
Blanco
A
A
Martínez
J
J
Pastor FIJ
Diaz
P
P
D000595:Amino Acid Sequence; D001407:Bacillus / Q000201:enzymology / Q000235:genetics*; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics*; D001426:Bacterial Proteins; D002265:Carboxylic Ester Hydrolases / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D003001:Cloning, Molecular; D016384:Consensus Sequence; D015723:Gene Library; D005798:Genes, Bacterial; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008969:Molecular Sequence Data; D016415:Sequence Alignment; D013696:Temperature
D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D002265:Carboxylic Ester Hydrolases; C098953:EstA protein, bacteria