1kbo
From Proteopedia
| Line 1: | Line 1: | ||
[[Image:1kbo.jpg|left|200px]] | [[Image:1kbo.jpg|left|200px]] | ||
| - | + | <!-- | |
| - | + | The line below this paragraph, containing "STRUCTURE_1kbo", creates the "Structure Box" on the page. | |
| - | + | You may change the PDB parameter (which sets the PDB file loaded into the applet) | |
| - | + | or the SCENE parameter (which sets the initial scene displayed when the page is loaded), | |
| - | + | or leave the SCENE parameter empty for the default display. | |
| - | | | + | --> |
| - | | | + | {{STRUCTURE_1kbo| PDB=1kbo | SCENE= }} |
| - | + | ||
| - | + | ||
| - | }} | + | |
'''Complex of Human recombinant NAD(P)H:Quinone Oxide reductase type 1 with 5-methoxy-1,2-dimethyl-3-(phenoxymethyl)indole-4,7-dione (ES1340)''' | '''Complex of Human recombinant NAD(P)H:Quinone Oxide reductase type 1 with 5-methoxy-1,2-dimethyl-3-(phenoxymethyl)indole-4,7-dione (ES1340)''' | ||
| Line 30: | Line 27: | ||
[[Category: Flavoenzyme]] | [[Category: Flavoenzyme]] | ||
[[Category: Prodrug-enzyme complex]] | [[Category: Prodrug-enzyme complex]] | ||
| - | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 22:32:56 2008'' | |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | |
Revision as of 19:32, 2 May 2008
Complex of Human recombinant NAD(P)H:Quinone Oxide reductase type 1 with 5-methoxy-1,2-dimethyl-3-(phenoxymethyl)indole-4,7-dione (ES1340)
Overview
We report the characterization of 5-methoxy-1,2-dimethyl-3-[(4-nitrophenoxy)methyl]indole-4,7-dione (ES936) as a mechanism-based inhibitor of NQO1. Inactivation of NQO1 by ES936 was time- and concentration-dependent and required the presence of a pyridine nucleotide cofactor consistent with a need for metabolic activation. That ES936 was an efficient inhibitor was demonstrated in these studies by the low partition ratio (1.40 +/- 0.03). The orientation of ES936 in the active site of NQO1 was examined by X-ray crystallography and found to be opposite to that observed for other indolequinones acting as substrates. ES936 was oriented in such a manner that, after enzymatic reduction and loss of a nitrophenol leaving group, a reactive iminium species was located in close proximity to nucleophilic His 162 and Tyr 127 and Tyr 129 residues in the active site. To determine if ES936 was covalently modifying NQO1, ES936-treated protein was analyzed by electrospray ionization liquid chromatography/mass spectrometry (ESI-LC/MS). The control NQO1 protein had a mass of 30864 +/- 6 Da (n = 20, theoretical, 30868.6 Da) which increased by 217 Da after ES936 treatment (31081 +/- 7 Da, n = 20) in the presence of NADH. The shift in mass was consistent with adduction of NQO1 by the reactive iminium derived from ES936 (M + 218 Da). Chymotryptic digestion of the protein followed by LC/MS analysis located a tetrapeptide spanning amino acids 126-129 which was adducted with the reactive iminium species derived from ES936. LC/MS/MS analysis of the peptide fragment confirmed adduction of either Tyr 127 or Tyr 129 residues. This work demonstrates that ES936 is a potent mechanism-based inhibitor of NQO1 and may be a useful tool in defining the role of NQO1 in cellular systems and in vivo.
About this Structure
1KBO is a Single protein structure of sequence from Homo sapiens. Full crystallographic information is available from OCA.
Reference
Characterization of a mechanism-based inhibitor of NAD(P)H:quinone oxidoreductase 1 by biochemical, X-ray crystallographic, and mass spectrometric approaches., Winski SL, Faig M, Bianchet MA, Siegel D, Swann E, Fung K, Duncan MW, Moody CJ, Amzel LM, Ross D, Biochemistry. 2001 Dec 18;40(50):15135-42. PMID:11735396 Page seeded by OCA on Fri May 2 22:32:56 2008
