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Crystal structure of the catalytic domain of human bile salt activated lipase
Author(s) -
Terzyan Simon,
Wang ChiSun,
Downs Deborah,
Hunter Bret,
Zhang Xuejun C.
Publication year - 2000
Publication title -
protein science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.353
H-Index - 175
eISSN - 1469-896X
pISSN - 0961-8368
DOI - 10.1110/ps.9.9.1783
Subject(s) - catalytic triad , oxyanion hole , hydrolase , chemistry , lipase , crystallization , molecular replacement , active site , stereochemistry , enzyme , salt (chemistry) , binding site , salt bridge , crystal structure , crystallography , biochemistry , organic chemistry , mutant , gene
Bile‐salt activated lipase (BAL) is a páncreatic enzyme that digests a variety of lipids in the small intestine. A distinct property of BAL is its dependency on bile salts in hydrolyzing substrates of long acyl chains or bulky alcoholic motifs. A crystal structure of the catalytic domain of human BAL (residues 1‐538) with two surface mutations (N186D and A298D), which were introduced in attempting to facilitate crystallization, has been determined at 2.3 Å resolution. The crystal form belongs to space group P2 1 2 1 2 1 with one monomer per asymmetric unit, and the protein shows an α/β hydrolase fold. In the absence of bound bile salt molecules, the protein possesses a preformed catalytic triad and a functional oxyanion hole. Several surface loops around the active site are mobile, including two loops potentially involved in substrate binding (residues 115‐125 and 270‐285).