The choline dehydrogenase BetA of Acinetobacter baumannii: a flavoprotein responsible for osmotic stress protection

  • Acinetobacter baumannii is outstanding for its ability to cope with low water activities which significantly contributes to its persistence in hospital environments. The vast majority of bacteria are able to prevent loss of cellular water by amassing osmoactive compatible solutes or their precursors into the cytoplasm. One such precursor of an osmoprotectant is choline that is taken up from the environment and oxidized to the compatible solute glycine betaine. Here, we report the identification of the osmotic stress operon betIBA in A. baumannii. This operon encodes the choline oxidation pathway important for the production of the solute glycine betaine. The salt-sensitive phenotype of a betA deletion strain could not be rescued by addition of choline, which is consistent with the role of BetA in choline oxidation. We found that BetA is a choline dehydrogenase but also mediates in vitro the oxidation of glycine betaine aldehyde to glycine betaine. BetA was found to be associated with the membrane and to contain a flavin, indicative for BetA donating electrons into the respiratory chain. The choline dehydrogenase activity was not salt dependent but was stimulated by the compatible solute glutamate.

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Author:Jennifer Breisch, Melanie Bendel, Beate AverhoffORCiD
Parent Title (English):Environmental microbiology
Place of publication:Oxford [u.a.]
Document Type:Article
Date of Publication (online):2021/08/25
Date of first Publication:2021/08/25
Publishing Institution:Universit├Ątsbibliothek Johann Christian Senckenberg
Release Date:2022/03/14
Issue:online version before inclusion in an issue
Page Number:10
First Page:1
Last Page:10
This study was supported by a grant from the Deutsche Forschungsgemeinschaft through DFG Research Unit FOR2251.
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Dewey Decimal Classification:5 Naturwissenschaften und Mathematik / 57 Biowissenschaften; Biologie / 570 Biowissenschaften; Biologie
6 Technik, Medizin, angewandte Wissenschaften / 61 Medizin und Gesundheit / 610 Medizin und Gesundheit
Licence (German):License LogoCreative Commons - Namensnennung 4.0