Structure and heme-binding properties of HemQ (chlorite dismutase-like protein) from Listeria monocytogenes

Stefan Hofbauer, Andreas Hagmüller, Irene Schaffner, Georg Mlynek, Michael Krutzler, Gerhard Stadlmayr, Katharina F. Pirker, Christian Obinger, Holger Daims, Kristina Djinovic-Carugo, Paul G. Furtmueller

Veröffentlichungen: Beitrag in FachzeitschriftArtikelPeer Reviewed

Abstract

Chlorite dismutase-like proteins are structurally closely related to functional chlorite dismutases which are heme b-dependent oxidoreductases capable of reducing chlorite to chloride with simultaneous production of dioxygen. Chlorite dismutase-like proteins are incapable of performing this reaction and their biological role is still under discussion. Recently, members of this large protein family were shown to be involved in heme biosynthesis in Gram-positive bacteria, and thus the protein was renamed HemQ in these organisms. In the present work the structural and heme binding properties of the chlorite dismutase-like protein from the Gram-positive pathogen Listeria monocytogenes (LmCld) were analyzed in order to evaluate its potential role as a regulatory heme sensing protein. The homopentameric crystal structure (2.0 Å) shows high similarity to chlorite-degrading chlorite dismutases with an important difference in the structure of the putative substrate and heme entrance channel. In solution LmCld is a stable hexamer able to bind the low-spin ligand cyanide. Heme binding is reversible with K D-values determined to be 7.2 μM (circular dichroism spectroscopy) and 16.8 μM (isothermal titration calorimetry) at pH 7.0. Both acidic and alkaline conditions promote heme release. Presented biochemical and structural data reveal that the chlorite dismutase-like protein from L. monocytogenes could act as a potential regulatory heme sensing and storage protein within heme biosynthesis.

OriginalspracheEnglisch
Seiten (von - bis)36-48
Seitenumfang13
FachzeitschriftArchives of Biochemistry and Biophysics
Jahrgang574
DOIs
PublikationsstatusVeröffentlicht - 15 Mai 2015

ÖFOS 2012

  • 106022 Mikrobiologie

Zitationsweisen