TY - JOUR
T1 - Structure of uncomplexed and linoleate-bound Candida cylindracea cholesterol esterase
AU - Ghosh, Debashis
AU - Wawrzak, Zdzislaw
AU - Pletnev, Vladimir Z.
AU - Li, Naiyin
AU - Kaiser, Rudolf
AU - Pangborn, Walter
AU - Jörnvall, Hans
AU - Erman, Mary
AU - Duax, William L.
N1 - Funding Information:
This work is funded by NIH grant No. DK26546 and by the Mae Stone Goode Trust Fund. We thank Drs JF Griffin and GD Smith for critically reading the manuscript and suggesting improvements. Thanks are also due to Prof. N-hu Xuong and his staff at the University of California at San Diego for help in data collection. Melda Tugac and Gloria Del Bel of the Graphics Department are thanked for their excellent work with the figure reproduction. Sandra Finken is thanked for the preparation of the manuscript.
PY - 1995/3
Y1 - 1995/3
N2 - Background: Candida cylindracea cholesterol esterase (CE) reversibly hydrolyzes cholesteryl linoleate and oleate. CE belongs to the same α/β 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 å and 2.0 å 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. Conclusion 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.
AB - Background: Candida cylindracea cholesterol esterase (CE) reversibly hydrolyzes cholesteryl linoleate and oleate. CE belongs to the same α/β 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 å and 2.0 å 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. Conclusion 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.
KW - X-ray structure
KW - cholesterol esterase
KW - cholesteryl linoleate
KW - dimer formation
KW - hydrolysis and esterification
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U2 - 10.1016/S0969-2126(01)00158-7
DO - 10.1016/S0969-2126(01)00158-7
M3 - Article
C2 - 7788294
AN - SCOPUS:0029644244
SN - 0969-2126
VL - 3
SP - 279
EP - 288
JO - Structure
JF - Structure
IS - 3
ER -