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Structure. 2012 May 9;20(5):767-79. doi: 10.1016/j.str.2012.02.020.

The structure of dimeric apolipoprotein A-IV and its mechanism of self-association.

Author information

1
Department of Molecular Genetics, Biochemistry, and Microbiology, College of Medicine, University of Cincinnati, OH 45267, USA.

Abstract

Apolipoproteins are key structural elements of lipoproteins and critical mediators of lipid metabolism. Their detergent-like properties allow them to emulsify lipid or exist in a soluble lipid-free form in various states of self-association. Unfortunately, these traits have hampered high-resolution structural studies needed to understand the biogenesis of cardioprotective high-density lipoproteins (HDLs). We derived a crystal structure of the core domain of human apolipoprotein (apo)A-IV, an HDL component and important mediator of lipid absorption. The structure at 2.4 Å depicts two linearly connected 4-helix bundles participating in a helix swapping arrangement that offers a clear explanation for how the protein self-associates as well as clues to the structure of its monomeric form. This also provides a logical basis for antiparallel arrangements recently described for lipid-containing particles. Furthermore, we propose a "swinging door" model for apoA-IV lipid association.

PMID:
22579246
PMCID:
PMC3354570
DOI:
10.1016/j.str.2012.02.020
[Indexed for MEDLINE]
Free PMC Article

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