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Crystal structure of truncated human apolipoprotein A-I suggests a lipid-bound conformation.

ABSTRACT: The structure of truncated human apolipoprotein A-I (apo A-I), the major protein component of high density lipoprotein, has been determined at 4-A resolution. The crystals comprise residues 44-243 (exon 4) of apo A-I, a fragment that binds to lipid similarly to intact apo A-I and that retains the lipid-bound conformation even in the absence of lipid. The molecule consists almost entirely of a pseudo-continuous, amphipathic alpha-helix that is punctuated by kinks at regularly spaced proline residues; it adopts a shape similar to a horseshoe of dimensions 125 x 80 x 40 A. Four molecules in the asymmetric unit associate via their hydrophobic faces to form an antiparallel four-helix bundle with an elliptical ring shape. Based on this structure, we propose a model for the structure of apo A-I bound to high density lipoprotein.

SUBMITTER: Borhani DW

PROVIDER: S-EPMC24911 | biostudies-literature | 1997 Nov

REPOSITORIES: biostudies-literature

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Crystal structure of truncated human apolipoprotein A-I suggests a lipid-bound conformation.

Borhani D W DW Rogers D P DP Engler J A JA Brouillette C G CG

Proceedings of the National Academy of Sciences of the United States of America 19971101 23

The structure of truncated human apolipoprotein A-I (apo A-I), the major protein component of high density lipoprotein, has been determined at 4-A resolution. The crystals comprise residues 44-243 (exon 4) of apo A-I, a fragment that binds to lipid similarly to intact apo A-I and that retains the lipid-bound conformation even in the absence of lipid. The molecule consists almost entirely of a pseudo-continuous, amphipathic alpha-helix that is punctuated by kinks at regularly spaced proline resid ...[more]

PMID: 9356442

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