| Role of histidines identified by mutagenesis in the NADPH oxidase-associated H+ channel. | |
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MedLine Citation:
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PMID: 9837891 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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The efflux of protons through a H+ channel acts as the charge compensation pathway for the electrogenic generation of superoxide (O-2) by human neutrophil NADPH oxidase. It has previously been shown that the N-terminal 230 amino acids of the product of the X-linked chronic granulomatous gene gp91(phox) contain all that is required for it to function as the arachidonate-activable, NADPH oxidase-associated H+ channel (Henderson, L. M., Thomas, S., Banting, G., and Chappell, J. B. (1997) Biochem. J. 325, 701-705). To identify functionally important amino acids, Chinese hamster ovary (CHO) cell lines were constructed that expressed point mutations in the N terminus of gp91(phox). No H+ flux was observed in CHO cell lines expressing the N-terminal gp91(phox) mutants H111L, H115L, and H119L, or H115L, or H115K. Partial retention of H+ channel function was, however, observed in the H115D CHO cell line. The addition of arachidonic acid to R91E,R92E CHO cells elicited a full H+ channel response. The buffering capacity and response of 2', 7'-bis(2-carboxyethyl)-5(6)-carboxyfluorescein to H+ were the same in all cell lines. Therefore, it can be concluded that His-115 is important to the ability of gp91(phox) to function as the NADPH oxidase-associated H+ channel and that the mechanism of H+ conduction involves protonation and deprotonation of an amino acid with an appropriate pK value. |
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Authors:
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L M Henderson |
Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: The Journal of biological chemistry Volume: 273 ISSN: 0021-9258 ISO Abbreviation: J. Biol. Chem. Publication Date: 1998 Dec |
Date Detail:
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Created Date: 1999-01-14 Completed Date: 1999-01-14 Revised Date: 2006-11-15 |
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: 33216-23 Citation Subset: IM |
Affiliation:
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Department of Biochemistry, School of Medical Sciences, University of Bristol, University Walk, Bristol BS8 1TD, United Kingdom. L.M.Henderson@bris.ac.uk |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Animals Arachidonic Acid / pharmacology Base Sequence CHO Cells Cricetinae DNA Primers Fluoresceins Fluorescent Dyes Histidine / chemistry Humans Hydrogen / metabolism* Ion Channels / drug effects, metabolism* Membrane Glycoproteins / chemistry, metabolism Mutagenesis, Site-Directed NADPH Oxidase / metabolism* |
| Chemical | |
Reg. No./Substance:
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0/CYBB protein, human; 0/DNA Primers; 0/Fluoresceins; 0/Fluorescent Dyes; 0/Ion Channels; 0/Membrane Glycoproteins; 1333-74-0/Hydrogen; 506-32-1/Arachidonic Acid; 71-00-1/Histidine; 85138-49-4/2',7'-bis(carboxyethyl)-5(6)-carboxyfluorescein; EC 1.6.3.1/NADPH Oxidase |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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