A cytochrome aa3-type quinol oxidase from Desulfurolobus ambivalens, the most acidophilic archaeon

S. Anemüller*, C. L. Schmidt, I. Pacheco, G. Schäfer, M. Teixeira

*Corresponding author for this work

Abstract

Membranes of the extremely thermoacidophilic archaeon Desulfurolobus ambivalens grown under aerobic conditions contain a quinol oxidase of the cytochrome aa3-type as the most prominent hemoprotein. The partially purified enzyme consists of three polypeptide subunits with apparent molecular masses of 40, 27 and 20 kDa and contains two heme A molecules and one copper atom. CO difference spectra suggest one heme to be a heme a3-centre. The EPR spectra indicate the presence of a low-spin and a high-spin heme species. Redox titrations of the solubilized enzyme show the presence of two reduction processes, with apparent potentials of + 235 and + 330 mV. The enzyme cannot oxidize reduced cytochrome c, but rather serves as an oxidase of caldariella quinone. Due to their very simple composition, D. ambivalens cell appear as a promising candidate to study Structure-function relationships of cytochrome aa3 in the integral membrane state.

Original languageEnglish
JournalFEMS Microbiology Letters
Volume117
Issue number3
Pages (from-to)275-280
Number of pages6
ISSN0378-1097
DOIs
Publication statusPublished - 15.04.1994

Research Areas and Centers

  • Academic Focus: Center for Infection and Inflammation Research (ZIEL)

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