Linked Life Data

2117468

Source:http://linkedlifedata.com/resource/pubmed/id/2117468

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
23
pubmed:dateCreated
1990-9-27
pubmed:databankReference
pubmed:abstractText
A gene coding for lipase-solubilized bovine liver microsomal cytochrome b5 has been synthesized, expressed in Escherichia coli, and mutated at functionally critical residues. Characterization of the recombinant protein revealed that it has a reduction potential that is approximately 17 mV lower than that of authentic wild-type protein at pH 7 (25 degrees C). Structural studies determined that the recombinant protein differed in sequence from authentic wild-type cytochrome b5 owing to three errors in amidation status in the published sequence for the protein on which the gene synthesis was based. The structural origin of the lower reduction potential exhibited by the triple mutant has been investigated through X-ray crystallographic determination of the three-dimensional structure of this protein and is attributed to the presence of Asp-57 within 3.3 A of heme vinyl-4 in the mutant. In addition, the model developed by Argos and Mathews [Argos, P., & Mathews, F.S. (1975) J. Biol. Chem. 250, 747] for the change in cytochrome b5 oxidation state has been studied through mutation of Ser-64 to Ala. In this model, Ser-64 is postulated to stabilize the oxidized protein through H-bonding interactions with heme propionate-7 that orients this propionate group 6.2 A from the heme iron. Spectroelectrochemical studies of a mutant in which Ser-64 has been changed to an alanyl residue demonstrate that this protein has a reduction potential that is 7 mV lower than that of the wild-type protein; moreover, conversion of the heme propionate groups to the corresponding methyl esters increases the potential by 67 mV.(ABSTRACT TRUNCATED AT 250 WORDS)
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
12
pubmed:volume
29
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
5500-8
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1990
pubmed:articleTitle
Mutagenic, electrochemical, and crystallographic investigation of the cytochrome b5 oxidation-reduction equilibrium: involvement of asparagine-57, serine-64, and heme propionate-7.
pubmed:affiliation
Department of Biochemistry, University of British Columbia, Vancouver, Canada.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't