| Joint functions of protein residues and NADP(H) in oxygen activation by flavin-containing monooxygenase. | |
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MedLine Citation:
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PMID: 20807767 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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The reactivity of flavoenzymes with dioxygen is at the heart of a number of biochemical reactions with far reaching implications for cell physiology and pathology. Flavin-containing monooxygenases are an attractive model system to study flavin-mediated oxygenation. In these enzymes, the NADP(H) cofactor is essential for stabilizing the flavin intermediate, which activates dioxygen and makes it ready to react with the substrate undergoing oxygenation. Our studies combine site-directed mutagenesis with the usage of NADP(+) analogues to dissect the specific roles of the cofactors and surrounding protein matrix. The highlight of this "double-engineering" approach is that subtle alterations in the hydrogen bonding and stereochemical environment can drastically alter the efficiency and outcome of the reaction with oxygen. This is illustrated by the seemingly marginal replacement of an Asn to Ser in the oxygen-reacting site, which inactivates the enzyme by effectively converting it into an oxidase. These data rationalize the effect of mutations that cause enzyme deficiency in patients affected by the fish odor syndrome. A crucial role of NADP(+) in the oxygenation reaction is to shield the reacting flavin N5 atom by H-bond interactions. A Tyr residue functions as backdoor that stabilizes this crucial binding conformation of the nicotinamide cofactor. A general concept emerging from this analysis is that the two alternative pathways of flavoprotein-oxygen reactivity (oxidation versus monooxygenation) are predicted to have very similar activation barriers. The necessity of fine tuning the hydrogen-bonding, electrostatics, and accessibility of the flavin will represent a challenge for the design and development of oxidases and monoxygenases for biotechnological applications. |
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Authors:
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Roberto Orru; Daniel E Torres Pazmiño; Marco W Fraaije; Andrea Mattevi |
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Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't Date: 2010-08-31 |
Journal Detail:
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Title: The Journal of biological chemistry Volume: 285 ISSN: 1083-351X ISO Abbreviation: J. Biol. Chem. Publication Date: 2010 Nov |
Date Detail:
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Created Date: 2010-11-01 Completed Date: 2010-11-30 Revised Date: 2011-11-07 |
Medline Journal Info:
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Nlm Unique ID: 2985121R Medline TA: J Biol Chem Country: United States |
Other Details:
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Languages: eng Pagination: 35021-8 Citation Subset: IM |
Affiliation:
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Department of Genetics and Microbiology, University of Pavia, Via Ferrata 1, 27100 Pavia, Italy. |
| Data Bank Information | |
Bank Name/Acc. No.:
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PDB/2XLP; 2XLR; 2XLS; 2XLT; 2XLU |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Amino Acid Substitution Bacteria / enzymology*, genetics Bacterial Proteins / chemistry*, genetics, metabolism Flavins / chemistry*, metabolism Mixed Function Oxygenases / chemistry*, genetics, metabolism Mutagenesis, Site-Directed NADP / chemistry*, metabolism Oxidation-Reduction Oxygen / chemistry*, metabolism |
| Chemical | |
Reg. No./Substance:
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0/Bacterial Proteins; 0/Flavins; 53-59-8/NADP; 7782-44-7/Oxygen; EC 1.-/Mixed Function Oxygenases |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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