title: The high-resolution crystal structure of human LCAT.
abstract: LCAT is intimately involved in HDL maturation and is a key component of the reverse cholesterol transport (RCT) pathway which removes excess cholesterol molecules from the peripheral tissues to the liver for excretion. Patients with loss-of-function LCAT mutations exhibit low levels of HDL cholesterol and corneal opacity. Here we report the 2.65 Å crystal structure of the human LCAT protein. Crystallization required enzymatic removal of N-linked glycans and complex formation with a Fab fragment from a tool antibody. The crystal structure reveals that LCAT has an α/β hydrolase core with two additional subdomains that play important roles in LCAT function. Subdomain 1 contains the region of LCAT shown to be required for interfacial activation, while subdomain 2 contains the lid and amino acids that shape the substrate binding pocket. Mapping the naturally occurring mutations onto the structure provides insight into how they may affect LCAT enzymatic activity.
authors.affiliation: Therapeutic Discovery Amgen Inc., South San Francisco, CA 94080.
authors.forename: Derek E
authors.initials: DE
authors.lastname: Piper
authors.affiliation: Therapeutic Discovery Amgen Inc., South San Francisco, CA 94080.
authors.forename: William G
authors.initials: WG
authors.lastname: Romanow
authors.affiliation: Therapeutic Discovery, Amgen Inc., Seattle, WA 98119.
authors.forename: Ruwanthi N
authors.initials: RN
authors.lastname: Gunawardane
authors.affiliation: Metabolic Disorders, Amgen Inc., South San Francisco, CA 94080.
authors.forename: Preston
authors.initials: P
authors.lastname: Fordstrom
authors.affiliation: Therapeutic Discovery, Amgen Inc., Burnaby, BC V5A1V7, Canada.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Masterman
authors.affiliation: Therapeutic Discovery, Amgen Inc., Burnaby, BC V5A1V7, Canada.
authors.forename: Oscar
authors.initials: O
authors.lastname: Pan
authors.affiliation: Therapeutic Discovery Amgen Inc., South San Francisco, CA 94080.
authors.forename: Stephen T
authors.initials: ST
authors.lastname: Thibault
authors.affiliation: Therapeutic Discovery Amgen Inc., South San Francisco, CA 94080.
authors.forename: Richard
authors.initials: R
authors.lastname: Zhang
authors.affiliation: Therapeutic Discovery, Amgen Inc., Seattle, WA 98119.
authors.forename: David
authors.initials: D
authors.lastname: Meininger
authors.affiliation: Metabolic Disorders, Amgen Inc., South San Francisco, CA 94080.
authors.forename: Margrit
authors.initials: M
authors.lastname: Schwarz
authors.affiliation: Therapeutic Discovery Amgen Inc., South San Francisco, CA 94080.
authors.forename: Zhulun
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Therapeutic Discovery, Amgen Inc., Burnaby, BC V5A1V7, Canada.
authors.forename: Chadwick
authors.initials: C
authors.lastname: King
authors.affiliation: Metabolic Disorders, Amgen Inc., South San Francisco, CA 94080.
authors.forename: Mingyue
authors.initials: M
authors.lastname: Zhou
authors.affiliation: Therapeutic Discovery Amgen Inc., South San Francisco, CA 94080.
authors.forename: Nigel P C
authors.initials: NP
authors.lastname: Walker
mesh_terms: D002784:Cholesterol / Q000235:genetics / Q000378:metabolism*; D018360:Crystallography, X-Ray; D006801:Humans; D009154:Mutation; D007862:Phosphatidylcholine-Sterol O-Acyltransferase / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D011485:Protein Binding; D011487:Protein Conformation; D015398:Signal Transduction
chemical_list: D002784:Cholesterol; D007862:Phosphatidylcholine-Sterol O-Acyltransferase
keywords: X-ray crystallography; antibodies; cholesterol; high density lipoprotein; lecithin:cholesterol acyltransferase