TY - JOUR
T1 - Characterization of the glutathione binding site of aldose reductase
AU - Ramana, Kota V.
AU - Dixit, Bharat L.
AU - Srivastava, Sanjay
AU - Bhatnagar, Aruni
AU - Balendiran, Ganesaratnam K.
AU - Watowich, Stanley J.
AU - Petrash, J. Mark
AU - Srivastava, Satish K.
N1 - Funding Information:
This study was supported in part by National Institutes of Health grants DK36118 (S.K.S.), HL55477 (A.B.), and HL59378 (A.B.).
Copyright:
Copyright 2007 Elsevier B.V., All rights reserved.
PY - 2001/1/30
Y1 - 2001/1/30
N2 - Despite extensive investigations, the physiological role of the polyol pathway enzyme-aldose reductase (AR) remains obscure. While the enzyme reduces glucose in vivo and in vitro, kinetic and structural studies indicate inefficient carbohydrate binding to the active site of the enzyme. The active site is lined by hydrophobic residues and appears more compatible with the binding of medium- to long-chain aliphatic aldehydes or hydrophobic aromatic aldehydes. In addition, our recent studies show that glutathione (GS) conjugates are also reduced efficiently by the enzyme. For instance, the GS conjugate of acrolein is reduced with a catalytic efficiency 1000-fold higher than the parent aldehyde, indicating specific recognition of glutathione by the active site residues of AR. An increase in the catalytic efficiency upon glutathiolation was also observed with trans-2-nonenal, trans-2-hexenal and trans, trans-2,4-decadienal, establishing that enhancement of catalytic efficiency was specifically due to the glutathione backbone and not specific to the aldehyde. Structure-activity relationships with substitution or deletion of amino acids of GSH indicated specific interactions of the active site with γ-Glu1 and Cys of GSH. Molecular modeling revealed that the glutathione-propanal conjugate could bind in two distinct orientations. In orientation 1, γ-Glu1 of the conjugate interacts with Trp20, Lys21 and Val47, and Gly3 interacts with Ser302 and Leu301, whereas in orientation 2, the molecule is inverted with γ-Glu1 interacting with Ser302, and Leu301. Taken together, these data suggest that glutathiolation of aldehydes enhances their compatibility with the AR active site, which may be of physiological significance in detoxification of endogenous and xenobiotic aldehydes.
AB - Despite extensive investigations, the physiological role of the polyol pathway enzyme-aldose reductase (AR) remains obscure. While the enzyme reduces glucose in vivo and in vitro, kinetic and structural studies indicate inefficient carbohydrate binding to the active site of the enzyme. The active site is lined by hydrophobic residues and appears more compatible with the binding of medium- to long-chain aliphatic aldehydes or hydrophobic aromatic aldehydes. In addition, our recent studies show that glutathione (GS) conjugates are also reduced efficiently by the enzyme. For instance, the GS conjugate of acrolein is reduced with a catalytic efficiency 1000-fold higher than the parent aldehyde, indicating specific recognition of glutathione by the active site residues of AR. An increase in the catalytic efficiency upon glutathiolation was also observed with trans-2-nonenal, trans-2-hexenal and trans, trans-2,4-decadienal, establishing that enhancement of catalytic efficiency was specifically due to the glutathione backbone and not specific to the aldehyde. Structure-activity relationships with substitution or deletion of amino acids of GSH indicated specific interactions of the active site with γ-Glu1 and Cys of GSH. Molecular modeling revealed that the glutathione-propanal conjugate could bind in two distinct orientations. In orientation 1, γ-Glu1 of the conjugate interacts with Trp20, Lys21 and Val47, and Gly3 interacts with Ser302 and Leu301, whereas in orientation 2, the molecule is inverted with γ-Glu1 interacting with Ser302, and Leu301. Taken together, these data suggest that glutathiolation of aldehydes enhances their compatibility with the AR active site, which may be of physiological significance in detoxification of endogenous and xenobiotic aldehydes.
KW - Aldehydes
KW - Aldose reductase
KW - Glutathione
KW - Regulation
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U2 - 10.1016/S0009-2797(00)00297-0
DO - 10.1016/S0009-2797(00)00297-0
M3 - Article
C2 - 11306073
AN - SCOPUS:0035969888
SN - 0009-2797
VL - 130-132
SP - 537
EP - 548
JO - Chemico-Biological Interactions
JF - Chemico-Biological Interactions
ER -