Linked Life Data

16584176

Source:http://linkedlifedata.com/resource/pubmed/id/16584176

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
14
pubmed:dateCreated
2006-4-4
pubmed:abstractText
A molecular modeling study of CYP27B1 suggests that Arg458 of mouse CYP27B1 is involved in interaction with adrenodoxin (ADX). Thus, we generated CYP27B1 mutants R458K and R458Q and revealed their enzymatic properties. Substrate-induced difference spectra and K(m) values for 1alpha-hydroxylation of 25(OH)D3 indicate that the replacement of Arg458 with Lys or Gln does not affect substrate binding. However, these mutants showed remarkable decreases of both kcat values and the ratio of product formation to NADPH oxidation (coupling efficiency). A high K(m) value of R458Q for ADX concentration and a decrease of rate constant of the first electron transfer seem reasonable considering that the conversion from Arg to noncharged Gln abolishes salt-bridge formation with the acidic residue of ADX. On the other hand, R458K showed atypical kinetics for ADX concentration with Hill's constant of 2.0 and high catalytic activity at high ADX concentration by increase of coupling efficiency. These results suggest that conformational change of R458K by binding the two ADX molecules is essential for 1alpha-hydroxylation of 25(OH)D3. On the other hand, binding one ADX molecule is sufficient for the conformational change of the wild-type CYP27B1, judging from its Michaelis-Menten-type kinetics for ADX concentration with high coupling efficiency. These results suggest that ADX functions as an effector for the oxygen transfer reaction in addition to being an electron donor for CYP27B1.
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
11
pubmed:volume
45
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
4405-12
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2006
pubmed:articleTitle
Interaction between mitochondrial CYP27B1 and adrenodoxin: role of arginine 458 of mouse CYP27B1.
pubmed:affiliation
Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't