BBB : Vol. 66 (2002) , No. 8 pp.1682-1690

Primary Structure and Catalytic Properties of a Cold-active Esterase from a Psychrotroph, Acinetobacter sp. Strain No. 6. Isolated from Siberian Soil

Takeshi SUZUKI¹⁾, Toru NAKAYAMA²⁾, Tatsuo KURIHARA¹⁾, Tokuzo NISHINO²⁾ and Nobuyoshi ESAKI¹⁾

1) Laboratory of Microbial Biochemistry, Institute for Chemical Research, Kyoto University
2) Department of Biomolecular Engineering, Graduate School of Engineering, Tohoku University

(Received February 6, 2002)
(Accepted March 27, 2002)

We cloned a gene coding for a cold-active esterase from a genomic library of Acinetobacter sp. strain No. 6, a psychrotroph isolated from Siberian soil. The gene, aest, encoded a protein of 301 amino acid residues, the deduced sequence of which had less than 17% identity to sequences of known esterases and lipases. However, the esterase seemed to belong to the α/β hydrolase superfamily, because it contained a sequence, Gly-Xaa-Ser-Xaa-Gly (with Xaa an arbitrary amino acid residue), found in most serine hydrolases of this superfamily. Sequence comparison earlier suggested a weak phylogenetic relationship of gene product AEST to the EST group of the esterase-lipase family, which has been found only in eukaryotes. The aest gene was expressed in Escherichia coli BL21(DE3) cells under the control of the T7 promoter, and the expression product was purified to homogeneity and characterized. It catalyzed the hydrolysis of esters with short-chain acyl groups and had lower activation energy and lower thermostability than do mesophilic enzymes, as expected from the cold-adapted nature of this enzyme.

Key words:

cold-active; esterase; prokaryotic; psychrotroph; superfamily

	To cite this article:
	Takeshi SUZUKI, Toru NAKAYAMA, Tatsuo KURIHARA, Tokuzo NISHINO and Nobuyoshi ESAKI, “Primary Structure and Catalytic Properties of a Cold-active Esterase from a Psychrotroph, Acinetobacter sp. Strain No. 6. Isolated from Siberian Soil”, Biosci. Biotechnol. Biochem., Vol. 66, 1682-1690 (2002) .

	doi:10.1271/bbb.66.1682
	JOI JST.JSTAGE/bbb/66.1682