TY - JOUR A1 - Breisch, Jennifer Maria A1 - Bendel, Melanie A1 - Averhoff, Beate T1 - The choline dehydrogenase BetA of Acinetobacter baumannii: a flavoprotein responsible for osmotic stress protection T2 - Environmental microbiology N2 - 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. Y1 - 2021 UR - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/64422 UR - https://nbn-resolving.org/urn:nbn:de:hebis:30:3-644223 SN - 1462-2920 N1 - This study was supported by a grant from the Deutsche Forschungsgemeinschaft through DFG Research Unit FOR2251. N1 - Early View-Version: Online Version of Record before inclusion in an issue. N1 - Version of Record: http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hebis:30:3-627973 IS - online version before inclusion in an issue SP - 1 EP - 10 PB - Blackwell CY - Oxford [u.a.] ER -