The impact of glycation on apolipoprotein A-I structure and its ability to activate lecithin: cholesterol acyltransferase
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The impact of glycation on apolipoprotein A-I structure and its ability to activate lecithin : cholesterol acyltransferase. / Nobecourt, E.; Davies, M. J.; Brown, B. E.; Curtiss, L. K.; Bonnet, D. J.; Charlton, F.; Januszewski, A. S.; Jenkins, A. J.; Barter, P. J.; Rye, K. -A.
In: Diabetologia, Vol. 50, No. 3, 03.2007, p. 643-653.Research output: Contribution to journal › Journal article › Research › peer-review
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TY - JOUR
T1 - The impact of glycation on apolipoprotein A-I structure and its ability to activate lecithin
T2 - cholesterol acyltransferase
AU - Nobecourt, E.
AU - Davies, M. J.
AU - Brown, B. E.
AU - Curtiss, L. K.
AU - Bonnet, D. J.
AU - Charlton, F.
AU - Januszewski, A. S.
AU - Jenkins, A. J.
AU - Barter, P. J.
AU - Rye, K. -A.
PY - 2007/3
Y1 - 2007/3
N2 - Aims/hypothesis Hyperglycaemia, one of the main features of diabetes, results in non-enzymatic glycation of plasma proteins, including apolipoprotein A-I (apoA-I), the most abundant apolipoprotein in HDL. The aim of this study was to determine how glycation affects the structure of apoA-I and its ability to activate lecithin:cholesterol acyltransferase (LCAT), a key enzyme in reverse cholesterol transport.Materials and methods Discoidal reconstituted HDL (rHDL) containing phosphatidylcholine and apoA-I ([A-I]rHDL) were prepared by the cholate dialysis method and glycated by incubation with methylglyoxal. Glycation of apoA-I was quantified as the reduction in detectable arginine, lysine and tryptophan residues. Methylglyoxal-AGE adduct formation in apoA-I was assessed by immunoblotting. (A-I)rHDL size and surface charge were determined by non-denaturing gradient gel electrophoresis and agarose gel electrophoresis, respectively. The kinetics of the LCAT reaction was investigated by incubating varying concentrations of discoidal (A-I)rHDL with a constant amount of purified enzyme. The conformation of apoA-I was assessed by surface plasmon resonance.Results Methylglyoxal-mediated modifications of the arginine, lysine and tryptophan residues in lipid-free and lipid-associated apoA-I were time- and concentration-dependent. These modifications altered the conformation of apoA-I in regions critical for LCAT activation and lipid binding. They also decreased (A-I)rHDL size and surface charge. The rate of LCAT-mediated cholesterol esterification in (A-I)rHDL varied according to the level of apoA-I glycation and progressively decreased as the extent of apoA-I glycation increased.Conclusions/interpretation It is concluded that glycation of apoA-I may adversely affect reverse cholesterol transport in subjects with diabetes.
AB - Aims/hypothesis Hyperglycaemia, one of the main features of diabetes, results in non-enzymatic glycation of plasma proteins, including apolipoprotein A-I (apoA-I), the most abundant apolipoprotein in HDL. The aim of this study was to determine how glycation affects the structure of apoA-I and its ability to activate lecithin:cholesterol acyltransferase (LCAT), a key enzyme in reverse cholesterol transport.Materials and methods Discoidal reconstituted HDL (rHDL) containing phosphatidylcholine and apoA-I ([A-I]rHDL) were prepared by the cholate dialysis method and glycated by incubation with methylglyoxal. Glycation of apoA-I was quantified as the reduction in detectable arginine, lysine and tryptophan residues. Methylglyoxal-AGE adduct formation in apoA-I was assessed by immunoblotting. (A-I)rHDL size and surface charge were determined by non-denaturing gradient gel electrophoresis and agarose gel electrophoresis, respectively. The kinetics of the LCAT reaction was investigated by incubating varying concentrations of discoidal (A-I)rHDL with a constant amount of purified enzyme. The conformation of apoA-I was assessed by surface plasmon resonance.Results Methylglyoxal-mediated modifications of the arginine, lysine and tryptophan residues in lipid-free and lipid-associated apoA-I were time- and concentration-dependent. These modifications altered the conformation of apoA-I in regions critical for LCAT activation and lipid binding. They also decreased (A-I)rHDL size and surface charge. The rate of LCAT-mediated cholesterol esterification in (A-I)rHDL varied according to the level of apoA-I glycation and progressively decreased as the extent of apoA-I glycation increased.Conclusions/interpretation It is concluded that glycation of apoA-I may adversely affect reverse cholesterol transport in subjects with diabetes.
KW - apolipoprotein A-I
KW - diabetes
KW - high-density lipoproteins
KW - lecithin : cholesterol acyltransferase
KW - non-enzymatic glycation
KW - HIGH-DENSITY-LIPOPROTEINS
KW - NONENZYMATIC GLYCOSYLATION
KW - MICELLAR COMPLEXES
KW - DIABETES-MELLITUS
KW - METHYLGLYOXAL
KW - PROTEINS
KW - BINDING
KW - VITRO
KW - AGE
KW - HDL
U2 - 10.1007/s00125-006-0574-z
DO - 10.1007/s00125-006-0574-z
M3 - Journal article
VL - 50
SP - 643
EP - 653
JO - Diabetologia
JF - Diabetologia
SN - 0012-186X
IS - 3
ER -
ID: 314392458