Document Detail


Role of histidines identified by mutagenesis in the NADPH oxidase-associated H+ channel.
MedLine Citation:
PMID:  9837891     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
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.
Authors:
L M Henderson
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The Journal of biological chemistry     Volume:  273     ISSN:  0021-9258     ISO Abbreviation:  J. Biol. Chem.     Publication Date:  1998 Dec 
Date Detail:
Created Date:  1999-01-14     Completed Date:  1999-01-14     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  2985121R     Medline TA:  J Biol Chem     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  33216-23     Citation Subset:  IM    
Affiliation:
Department of Biochemistry, School of Medical Sciences, University of Bristol, University Walk, Bristol BS8 1TD, United Kingdom. L.M.Henderson@bris.ac.uk
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MeSH Terms
Descriptor/Qualifier:
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:
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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