Back to Search Start Over

Transfer of C-terminal residues of human apolipoprotein A-I to insect apolipophorin III creates a two-domain chimeric protein with enhanced lipid binding activity.

Authors :
Horn JVC
Ellena RA
Tran JJ
Beck WHJ
Narayanaswami V
Weers PMM
Source :
Biochimica et biophysica acta. Biomembranes [Biochim Biophys Acta Biomembr] 2017 Aug; Vol. 1859 (8), pp. 1317-1325. Date of Electronic Publication: 2017 Apr 21.
Publication Year :
2017

Abstract

Apolipophorin III (apoLp-III) is an insect apolipoprotein (18kDa) that comprises a single five-helix bundle domain. In contrast, human apolipoprotein A-I (apoA-I) is a 28kDa two-domain protein: an α-helical N-terminal domain (residues 1-189) and a less structured C-terminal domain (residues 190-243). To better understand the apolipoprotein domain organization, a novel chimeric protein was engineered by attaching residues 179 to 243 of apoA-I to the C-terminal end of apoLp-III. The apoLp-III/apoA-I chimera was successfully expressed and purified in E. coli. Western blot analysis and mass spectrometry confirmed the presence of the C-terminal domain of apoA-I within the chimera. While parent apoLp-III did not self-associate, the chimera formed oligomers similar to apoA-I. The chimera displayed a lower α-helical content, but the stability remained similar compared to apoLp-III, consistent with the addition of a less structured domain. The chimera was able to solubilize phospholipid vesicles at a significantly higher rate compared to apoLp-III, approaching that of apoA-I. The chimera was more effective in protecting phospholipase C-treated low density lipoprotein from aggregation compared to apoLp-III. In addition, binding interaction of the chimera with phosphatidylglycerol vesicles and lipopolysaccharides was considerably improved compared to apoLp-III. Thus, addition of the C-terminal domain of apoA-I to apoLp-III created a two-domain protein, with self-association, lipid and lipopolysaccharide binding properties similar to apoA-I. The apoA-I like behavior of the chimera indicate that these properties are independent from residues residing in the N-terminal domain of apoA-I, and that they can be transferred from apoA-I to apoLp-III.<br /> (Copyright © 2017 Elsevier B.V. All rights reserved.)

Details

Language :
English
ISSN :
0005-2736
Volume :
1859
Issue :
8
Database :
MEDLINE
Journal :
Biochimica et biophysica acta. Biomembranes
Publication Type :
Academic Journal
Accession number :
28434970
Full Text :
https://doi.org/10.1016/j.bbamem.2017.04.017