Structural highlights
Function
NAO_FUSOX Catalyzes the oxidative denitrification of neutral nitroalkanes, including 3-nitro-2-pentanol, 1-nitropropane, 2-nitropropane, nitroethane and nitrocyclohexane, and may thereby protect the organism against toxic compounds. Has no detectable acyl-CoA dehydrogenase activity.[1] [2] [3]
Evolutionary Conservation
Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.
Publication Abstract from PubMed
The flavoprotein nitroalkane oxidase (NAO) catalyzes the oxidation of primary and secondary nitroalkanes to the corresponding aldehydes and ketones. The enzyme is a homologue of acyl-CoA dehydrogenase. Asp402 in NAO has been proposed to be the active site base responsible for removing the substrate proton in the first catalytic step; structurally it corresponds to the glutamate which acts as the base in medium chain acyl-CoA dehydrogenase. In the active site of NAO, the carboxylate of Asp402 forms an ionic interaction with the side chain of Arg409. The R409K enzyme has now been characterized kinetically and structurally. The mutation results in a decrease in the rate constant for proton abstraction of 100-fold. Analysis of the three-dimensional structure of the R409K enzyme, determined by X-ray crystallography to a resolution of 2.65 A, shows that the critical structural change is an increase in the distance between the carboxylate of Asp402 and the positively charged nitrogen in the side chain of the residue at position 409. The D402E mutation results in a smaller decrease in the rate constant for proton abstraction of 18-fold. The structure of the D402E enzyme, determined at 2.4 A resolution, shows that there is a smaller increase in the distance between Arg409 and the carboxylate at position 402, and the interaction of this residue with Ser276 is perturbed. These results establish the critical importance of the interaction between Asp402 and Arg409 for proton abstraction by nitroalkane oxidase.
Mechanistic and structural analyses of the roles of Arg409 and Asp402 in the reaction of the flavoprotein nitroalkane oxidase.,Fitzpatrick PF, Bozinovski DM, Heroux A, Shaw PG, Valley MP, Orville AM Biochemistry. 2007 Dec 4;46(48):13800-8. Epub 2007 Nov 10. PMID:17994768[4]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Daubner SC, Gadda G, Valley MP, Fitzpatrick PF. Cloning of nitroalkane oxidase from Fusarium oxysporum identifies a new member of the acyl-CoA dehydrogenase superfamily. Proc Natl Acad Sci U S A. 2002 Mar 5;99(5):2702-7. Epub 2002 Feb 26. PMID:11867731 doi:http://dx.doi.org/10.1073/pnas.052527799
- ↑ Kido T, Hashizume K, Soda K. Purification and properties of nitroalkane oxidase from Fusarium oxysporum. J Bacteriol. 1978 Jan;133(1):53-8. PMID:22538
- ↑ Nagpal A, Valley MP, Fitzpatrick PF, Orville AM. Crystal structures of nitroalkane oxidase: insights into the reaction mechanism from a covalent complex of the flavoenzyme trapped during turnover. Biochemistry. 2006 Jan 31;45(4):1138-50. PMID:16430210 doi:10.1021/bi051966w
- ↑ Fitzpatrick PF, Bozinovski DM, Heroux A, Shaw PG, Valley MP, Orville AM. Mechanistic and structural analyses of the roles of Arg409 and Asp402 in the reaction of the flavoprotein nitroalkane oxidase. Biochemistry. 2007 Dec 4;46(48):13800-8. Epub 2007 Nov 10. PMID:17994768 doi:10.1021/bi701557k
