PMID: 21914797

Authors:

Mei X, Atkinson D

Title:

Crystal structure of C-terminal truncated apolipoprotein A-I reveals the assembly of HDL by dimerization.

Journal:

J Biol Chem. 2011 Sep 13.

Abstract:

Apolipoprotein A-I (apoA-I) plays important structural and functional roles in plasma high-density lipoprotein (HDL) that is responsible for reverse cholesterol transport. However, a molecular understanding of HDL assembly and function remains enigmatic. The 2.2A crystal structure of Delta(185-243)apoA-I reported here shows that it forms a half circle dimer. The backbone of the dimer consists of two elongated antiparallel proline-kinked helices (5 AB tandem repeats). The N-terminal domain of each molecule forms a four-helix bundle with the helical C-terminal region of the symmetry related partner. The central region forms a flexible domain with two antiparallel helices connecting the bundles at each end. The two-domain, dimer structure based on helical repeats suggests the role of apoA-I in the formation of discoidal HDL particles. Furthermore, the structure suggests the possible interaction with lecithin-cholesterol acyltransferase (LCAT), and may shed light on the molecular details of the effect of the Milano, Paris and Fin mutations.