Mechanism of steroidogenic electron transport: Role of conserved Glu429 in destabilization of CYP11A1-adrenodoxin complex

N. V. Strushkevich, I. N. Harnastai, S. A. Usanov

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)

Abstract

In the present work the role of conserved residue E429 of cytochrome P45011A1 has been studied. The charge neutralization of E429Q results in 3-fold decrease of Kd as well as Vmax compared to the wild type hemoprotein indicating tighter binding and, as the result, the impaired dissociation of oxidized adrenodoxin from the complex. As cytochrome P45011A1-adrenodoxin complex formation is driven primarily by electrostatic interactions, the low activity of E429Q mutant is completely restored to that of wild type hemoprotein by increasing of ionic strength. The charge neutralization of the corresponding residue of rat cytochrome P45011B2 has the same effect: the activity is 10-fold decreased but it is restored by increasing of ionic strength without effect on the ratio of products formed. Thus, this is the first report on identification of residues involved in modulation of dissociation of redox partner from the complex with cytochrome P450s.

Original languageEnglish
Pages (from-to)570-578
Number of pages9
JournalBiochemistry (Moscow)
Volume75
Issue number5
DOIs
Publication statusPublished - May 2010
Externally publishedYes

Keywords

  • Adrenodoxin
  • Cytochrome P450
  • Cytochrome P45011A1
  • Cytochrome P45011B2
  • Electron transfer
  • Protein-protein interactions
  • Site-directed mutagenesis

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