Publications

• AKR1A1 is a novel mammalian <i>S</i>-nitroso-glutathione reductase.

  Stomberski C.T., Anand P., Venetos N.M., Hausladen A., Zhou H.L., Premont R.T., Stamler J.S.

  Oxidative modification of Cys residues by NO results in <i>S</i>-nitrosylation, a ubiquitous post-translational modification and a primary mediator of redox-based cellular signaling. Steady-state levels of <i>S</i>-nitrosylated proteins are largely determined by denitrosylase enzymes that couple N ... >> More

  Oxidative modification of Cys residues by NO results in <i>S</i>-nitrosylation, a ubiquitous post-translational modification and a primary mediator of redox-based cellular signaling. Steady-state levels of <i>S</i>-nitrosylated proteins are largely determined by denitrosylase enzymes that couple NAD(P)H oxidation with reduction of <i>S</i>-nitrosothiols, including protein and low-molecular-weight (LMW) <i>S</i>-nitrosothiols (<i>S</i>-nitroso-GSH (GSNO) and <i>S</i>-nitroso-CoA (SNO-CoA)). SNO-CoA reductases require NADPH, whereas enzymatic reduction of GSNO can involve either NADH or NADPH. Notably, GSNO reductase (GSNOR, <i>Adh5</i>) accounts for most NADH-dependent GSNOR activity, whereas NADPH-dependent GSNOR activity is largely unaccounted for (CBR1 mediates a minor portion). Here, we <i>de novo</i> purified NADPH-coupled GSNOR activity from mammalian tissues and identified aldo-keto reductase family 1 member A1 (AKR1A1), the archetypal mammalian SNO-CoA reductase, as a primary mediator of NADPH-coupled GSNOR activity in these tissues. Kinetic analyses suggested an AKR1A1 substrate preference of SNO-CoA > GSNO. AKR1A1 deletion from murine tissues dramatically lowered NADPH-dependent GSNOR activity. Conversely, GSNOR-deficient mice had increased AKR1A1 activity, revealing potential cross-talk among GSNO-dependent denitrosylases. Molecular modeling and mutagenesis of AKR1A1 identified Arg-312 as a key residue mediating the specific interaction with GSNO; in contrast, substitution of the SNO-CoA-binding residue Lys-127 minimally affected the GSNO-reducing activity of AKR1A1. Together, these findings indicate that AKR1A1 is a multi-LMW-SNO reductase that can distinguish between and metabolize the two major LMW-SNO signaling molecules GSNO and SNO-CoA, allowing for wide-ranging control of protein <i>S</i>-nitrosylation under both physiological and pathological conditions. << Less

  J Biol Chem 294:18285-18293(2019) [PubMed] [EuropePMC]

• Human carbonyl reductase 1 is an S-nitrosoglutathione reductase.

  Bateman R.L., Rauh D., Tavshanjian B., Shokat K.M.

  Human carbonyl reductase 1 (hCBR1) is an NADPH-dependent short chain dehydrogenase/reductase with broad substrate specificity and is thought to be responsible for the in vivo reduction of quinones, prostaglandins, and other carbonyl-containing compounds including xenobiotics. In addition, hCBR1 po ... >> More

  Human carbonyl reductase 1 (hCBR1) is an NADPH-dependent short chain dehydrogenase/reductase with broad substrate specificity and is thought to be responsible for the in vivo reduction of quinones, prostaglandins, and other carbonyl-containing compounds including xenobiotics. In addition, hCBR1 possesses a glutathione binding site that allows for increased affinity toward GSH-conjugated molecules. It has been suggested that the GSH-binding site is near the active site; however, no structures with GSH or GSH conjugates have been reported. We have solved the x-ray crystal structures of hCBR1 and a substrate mimic in complex with GSH and the catalytically inert GSH conjugate hydroxymethylglutathione (HMGSH). The structures reveal the GSH-binding site and provide insight into the affinity determinants for GSH-conjugated substrates. We further demonstrate that the structural isostere of HMGSH, S-nitrosoglutathione, is an ideal hCBR1 substrate (Km = 30 microm, kcat = 450 min(-1)) with kinetic constants comparable with the best known hCBR1 substrates. Furthermore, we demonstrate that hCBR1 dependent GSNO reduction occurs in A549 lung adenocarcinoma cell lysates and suggest that hCBR1 may be involved in regulation of tissue levels of GSNO. << Less

  J. Biol. Chem. 283:35756-35762(2008) [PubMed] [EuropePMC]