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Title: Apolipoprotein AI tertiary structures determine stability and phospholipid-binding activity of discoidal high-density lipoprotein particles of different sizes

Abstract

Human high-density lipoprotein (HDL) plays a key role in the reverse cholesterol transport pathway that delivers excess cholesterol back to the liver for clearance. In vivo, HDL particles vary in size, shape and biological function. The discoidal HDL is a 140-240 kDa, disk-shaped intermediate of mature HDL. During mature spherical HDL formation, discoidal HDLs play a key role in loading cholesterol ester onto the HDL particles by activating the enzyme, lecithin:cholesterol acyltransferase (LCAT). One of the major problems for high-resolution structural studies of discoidal HDL is the difficulty in obtaining pure and, foremost, homogenous sample. We demonstrate here that the commonly used cholate dialysis method for discoidal HDL preparation usually contains 5-10% lipid-poor apoAI that significantly interferes with the high-resolution structural analysis of discoidal HDL using biophysical methods. Using an ultracentrifugation method, we quickly removed lipid-poor apoAI. We also purified discoidal reconstituted HDL (rHDL) into two pure discoidal HDL species of different sizes that are amendable for high-resolution structural studies. A small rHDL has a diameter of 7.6 nm, and a large rHDL has a diameter of 9.8 nm. We show that these two different sizes of discoidal HDL particles display different stability and phospholipid-binding activity. Interestingly, these property/functional differencesmore » are independent from the apoAI -helical secondary structure, but are determined by the tertiary structural difference of apoAI on different discoidal rHDL particles, as evidenced by two-dimensional NMR and negative stain electron microscopy data. Our result further provides the first high-resolution NMR data, demonstrating a promise of structural determination of discoidal HDL at atomic resolution using a combination of NMR and other biophysical techniques.« less

Authors:
; ; ; ; ; ; ;
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Environmental Molecular Sciences Lab. (EMSL)
Sponsoring Org.:
USDOE
OSTI Identifier:
958440
Report Number(s):
PNNL-SA-56783
2425; 7790a; 2016; 2128; 2128a; 2128b; 2136; 2298; 2299; 10593; 10593a; 10594; 3999; 3367; 9592; 7791; KP1704020; TRN: US201002%%143
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Journal Name:
Protein Science, 18(5):921-935
Additional Journal Information:
Journal Volume: 18; Journal Issue: 5
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; 99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE; APOLIPOPROTEINS; BIOLOGICAL FUNCTIONS; CHOLESTEROL; CLEARANCE; DIALYSIS; ELECTRON MICROSCOPY; ESTERS; IN VIVO; LIPOPROTEINS; LIVER; RESOLUTION; SHAPE; STABILITY; STAINS; TRANSPORT; ULTRACENTRIFUGATION; Environmental Molecular Sciences Laboratory

Citation Formats

Chen, Bin, Ren, Xuefeng, Neville, Tracey, Jerome, W Gray, Hoyt, David W, Sparks, Daniel L, Ren, Gang, and Wang, Jianjun. Apolipoprotein AI tertiary structures determine stability and phospholipid-binding activity of discoidal high-density lipoprotein particles of different sizes. United States: N. p., 2009. Web. doi:10.1002/pro.101.
Chen, Bin, Ren, Xuefeng, Neville, Tracey, Jerome, W Gray, Hoyt, David W, Sparks, Daniel L, Ren, Gang, & Wang, Jianjun. Apolipoprotein AI tertiary structures determine stability and phospholipid-binding activity of discoidal high-density lipoprotein particles of different sizes. United States. https://doi.org/10.1002/pro.101
Chen, Bin, Ren, Xuefeng, Neville, Tracey, Jerome, W Gray, Hoyt, David W, Sparks, Daniel L, Ren, Gang, and Wang, Jianjun. 2009. "Apolipoprotein AI tertiary structures determine stability and phospholipid-binding activity of discoidal high-density lipoprotein particles of different sizes". United States. https://doi.org/10.1002/pro.101.
@article{osti_958440,
title = {Apolipoprotein AI tertiary structures determine stability and phospholipid-binding activity of discoidal high-density lipoprotein particles of different sizes},
author = {Chen, Bin and Ren, Xuefeng and Neville, Tracey and Jerome, W Gray and Hoyt, David W and Sparks, Daniel L and Ren, Gang and Wang, Jianjun},
abstractNote = {Human high-density lipoprotein (HDL) plays a key role in the reverse cholesterol transport pathway that delivers excess cholesterol back to the liver for clearance. In vivo, HDL particles vary in size, shape and biological function. The discoidal HDL is a 140-240 kDa, disk-shaped intermediate of mature HDL. During mature spherical HDL formation, discoidal HDLs play a key role in loading cholesterol ester onto the HDL particles by activating the enzyme, lecithin:cholesterol acyltransferase (LCAT). One of the major problems for high-resolution structural studies of discoidal HDL is the difficulty in obtaining pure and, foremost, homogenous sample. We demonstrate here that the commonly used cholate dialysis method for discoidal HDL preparation usually contains 5-10% lipid-poor apoAI that significantly interferes with the high-resolution structural analysis of discoidal HDL using biophysical methods. Using an ultracentrifugation method, we quickly removed lipid-poor apoAI. We also purified discoidal reconstituted HDL (rHDL) into two pure discoidal HDL species of different sizes that are amendable for high-resolution structural studies. A small rHDL has a diameter of 7.6 nm, and a large rHDL has a diameter of 9.8 nm. We show that these two different sizes of discoidal HDL particles display different stability and phospholipid-binding activity. Interestingly, these property/functional differences are independent from the apoAI -helical secondary structure, but are determined by the tertiary structural difference of apoAI on different discoidal rHDL particles, as evidenced by two-dimensional NMR and negative stain electron microscopy data. Our result further provides the first high-resolution NMR data, demonstrating a promise of structural determination of discoidal HDL at atomic resolution using a combination of NMR and other biophysical techniques.},
doi = {10.1002/pro.101},
url = {https://www.osti.gov/biblio/958440}, journal = {Protein Science, 18(5):921-935},
number = 5,
volume = 18,
place = {United States},
year = {Mon May 18 00:00:00 EDT 2009},
month = {Mon May 18 00:00:00 EDT 2009}
}