Crystal Structure of Human Liver Carboxylesterase in complexed with naloxone methiodide, a heroin analogue

Structural Basis of Heroin and Cocaine Metabolism by a Promiscuous Human Drug-Processing Enzyme

hCEv, Acyl coenzyme A:cholesterol acyltransferase, ACAT, Monocyte/macrophage serine esterase, HMSE, Serine esterase 1

PEG3350, Glycerol, lithium sulfate, lithium chloride, sodium chloride, sodium citrate, pH 5.5, VAPOR DIFFUSION, SITTING DROP, temperature 298.0K

The same protein complexed with tacrine.

The same protein complexed with homatropine.

BIOMOLECULE: 1, 2
THIS ENTRY CONTAINS THE CRYSTALLOGRAPHIC ASYMMETRIC UNIT
WHICH CONSISTS OF 12 CHAIN(S). SEE REMARK 350 FOR
INFORMATION ON GENERATING THE BIOLOGICAL MOLECULE(S).

The authors have confirmed that human carboxylesterase 1
will form a trimer or hexamer in solution by Atomic Force
Microscopy (AFM). They found the ratio of
monomer:trimer:hexmer is ~ 10:44:46. 1MX1 contains a
hexamer, 1MX5 contains 2 trimers. This entry contains
two hexamers. The authors found that the trimer:hexmer
ratio is dependent on the type and amount of ligands.

SEQUENCE
THE AUTHOR'S SEQUENCE HAS NO GLN 362
(CALLED hCEv in: Kroetz DL, McBride OW,
Gonzalez FJ.Glycosylation-dependent
activity of baculovirus-expressed human
liver carboxylesterases: cDNA cloning
and characterization of two highly
similar enzyme forms. Biochemistry
1993 Nov 2;32(43):11606-17)

The biological assembly is two hexamers formed by four trimers in one asymmetric unit.