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'''STRUCTURE OF UNCOMPLEXED AND LINOLEATE-BOUND CANDIDA CYLINDRACEA CHOLESTEROL ESTERASE''' | '''STRUCTURE OF UNCOMPLEXED AND LINOLEATE-BOUND CANDIDA CYLINDRACEA CHOLESTEROL ESTERASE''' | ||
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[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Ghosh, D.]] | [[Category: Ghosh, D.]] | ||
[[Category: | [[Category: Esterase]] | ||
[[Category: | [[Category: Substrate/product-bound]] | ||
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 12:51:42 2008'' | |||
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | |||
Revision as of 12:51, 2 May 2008
STRUCTURE OF UNCOMPLEXED AND LINOLEATE-BOUND CANDIDA CYLINDRACEA CHOLESTEROL ESTERASE
OverviewOverview
BACKGROUND: Candida cylindracea cholesterol esterase (CE) reversibly hydrolyzes cholesteryl linoleate and oleate. CE belongs to the same alpha/beta hydrolase superfamily as triacylglycerol acyl hydrolases and cholinesterases. Other members of the family that have been studied by X-ray crystallography include Torpedo californica acetylcholinesterase, Geotrichum candidum lipase and Candida rugosa lipase. CE is homologous to C. rugosa lipase 1, a triacylglycerol acyl hydrolase, with which it shares 89% sequence identity. The present study explores the details of dimer formation of CE and the basis for its substrate specificity. RESULTS: The structures of uncomplexed and linoleate-bound CE determined at 1.9 A and 2.0 A resolution, respectively, reveal a dimeric association of monomers in which two active-site gorges face each other, shielding hydrophobic surfaces from the aqueous environment. The fatty-acid chain is buried in a deep hydrophobic pocket near the active site. The positioning of the cholesteryl moiety of the substrate is equivocal, but could be modeled in the hydrophobic core of the dimer interface. CONCLUSIONS: The monomer structure is the same in both the complexed and uncomplexed crystal forms. The dimers differ in the relative positions of the two monomers at the dimer interface. Of the 55 residues that are different in CE from those in C. rugosa lipase 1, 23 are located in the active site and at the dimer interface. The altered substrate specificity is a direct consequence of these substitutions.
About this StructureAbout this Structure
1CLE is a Single protein structure of sequence from Candida cylindracea. Full crystallographic information is available from OCA.
ReferenceReference
Structure of uncomplexed and linoleate-bound Candida cylindracea cholesterol esterase., Ghosh D, Wawrzak Z, Pletnev VZ, Li N, Kaiser R, Pangborn W, Jornvall H, Erman M, Duax WL, Structure. 1995 Mar 15;3(3):279-88. PMID:7788294 Page seeded by OCA on Fri May 2 12:51:42 2008