Linked Life Data

9136868

Source:http://linkedlifedata.com/resource/pubmed/id/9136868

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
17
pubmed:dateCreated
1997-6-3
pubmed:abstractText
The oxygenase domain of the mouse cytokine-inducible nitric-oxide synthase (iNOSox, amino acids 1-498) binds heme, tetrahydrobiopterin, and the substrate Arg and is the domain responsible for catalyzing nitric oxide synthesis and maintaining the enzyme's active dimeric structure. To further understand iNOSox structure-function, we carried out alanine point mutagenesis on 15 conserved acidic residues located within a region of iNOSox (amino acids 352-473) that shares sequence homology with the pterin-binding module in dihydrofolate reductases and may be important for iNOSox subunit dimerization and/or Arg binding. Five point mutants were identical or nearly identical to wild-type, while 10 exhibited a range of defects that included low heme content (2), heme ligand instability (2), defective dimerization (2), and poor Arg and/or tetrahydrobiopterin binding (4). Mutations that caused defective tetrahydrobiopterin binding were also associated with other defects. In contrast, two mutants (E371A and D376A) exhibited an exclusive defect in Arg binding. These mutants were dimeric, indicating that dimerization of iNOSox in Escherichia coli does not require Arg. In one case (E371A), the defect in Arg binding was absolute, as assessed by spectral perturbation, radioligand binding, and catalytic studies. We conclude that mutagenesis of conserved acidic residues within this region of iNOSox can lead to exclusive defects in dimerization and in Arg binding. Modeling considerations predict that the E371 carboxylate may participate in Arg binding by interacting with its guanidine moiety.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
29
pubmed:volume
36
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
5097-103
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1997
pubmed:articleTitle
Mutagenesis of acidic residues in the oxygenase domain of inducible nitric-oxide synthase identifies a glutamate involved in arginine binding.
pubmed:affiliation
Department of Immunology, The Cleveland Clinic Research Institute, Ohio 44195, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't