6P2P image
Entry Detail
PDB ID:
6P2P
EMDB ID:
Keywords:
Title:
Tetrameric structure of ACAT1
Biological Source:
Source Organism:
Host Organism:
PDB Version:
Deposition Date:
2019-05-21
Release Date:
2020-05-20
Method Details:
Experimental Method:
Resolution:
3.10 Å
Aggregation State:
PARTICLE
Reconstruction Method:
SINGLE PARTICLE
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:Sterol O-acyltransferase 1
Chain IDs:A, B, C, D
Chain Length:594
Number of Molecules:4
Biological Source:Homo sapiens
Ligand Molecules
Primary Citation
Structural basis for catalysis and substrate specificity of human ACAT1.
Nature 581 333 338 (2020)
PMID: 32433614 DOI: 10.1038/s41586-020-2290-0

Abstact

As members of the membrane-bound O-acyltransferase (MBOAT) enzyme family, acyl-coenzyme A:cholesterol acyltransferases (ACATs) catalyse the transfer of an acyl group from acyl-coenzyme A to cholesterol to generate cholesteryl ester, the primary form in which cholesterol is stored in cells and transported in plasma1. ACATs have gained attention as potential drug targets for the treatment of diseases such as atherosclerosis, Alzheimer's disease and cancer2-7. Here we present the cryo-electron microscopy structure of human ACAT1 as a dimer of dimers. Each protomer consists of nine transmembrane segments, which enclose a cytosolic tunnel and a transmembrane tunnel that converge at the predicted catalytic site. Evidence from structure-guided mutational analyses suggests that acyl-coenzyme A enters the active site through the cytosolic tunnel, whereas cholesterol may enter from the side through the transmembrane tunnel. This structural and biochemical characterization helps to rationalize the preference of ACAT1 for unsaturated acyl chains, and provides insight into the catalytic mechanism of enzymes within the MBOAT family8.

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Primary Citation of related structures