Crystal Structure of C-terminal Truncated Apolipoprotein A-I Reveals the Assembly of High Density Lipoprotein (HDL) by Dimerization.Mei, X., Atkinson, D.
(2011) J Biol Chem 286: 38570-38582
- PubMed: 21914797
- DOI: https://doi.org/10.1074/jbc.M111.260422
- Primary Citation of Related Structures:
- PubMed 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 2.2-Å crystal structure of Δ(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 (five 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 and may shed light on the molecular details of the effect of the Milano, Paris, and Fin mutations.
Department of Physiology and Biophysics, Boston University School of Medicine, Boston, Massachusetts 02118.