The malate sensing two-component system MaeKR is a non-canonical class of sensory complex for C4-dicarboxylates
Microbial colonization of different environments is enabled to a great extent by the plasticity of their sensory mechanisms, among them, the two-component signal transduction systems (TCS). Here, an example of TCS plasticity is presented: the regulation of L-malate catabolism via malic enzyme by Mae...
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Published in | Scientific reports Vol. 7; no. 1; pp. 2708 - 16 |
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Main Authors | , , , , , |
Format | Journal Article |
Language | English |
Published |
London
Nature Publishing Group UK
02.06.2017
Nature Publishing Group Nature Portfolio |
Subjects | |
Online Access | Get full text |
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Summary: | Microbial colonization of different environments is enabled to a great extent by the plasticity of their sensory mechanisms, among them, the two-component signal transduction systems (TCS). Here, an example of TCS plasticity is presented: the regulation of L-malate catabolism via malic enzyme by MaeRK in
Lactobacillales
. MaeKR belongs to the citrate family of TCS as the
Escherichia coli
DcuSR system. We show that the
Lactobacillus casei
histidine-kinase MaeK is defective in autophosphorylation activity as it lacks a functional catalytic and ATP binding domain. The cognate response regulator MaeR was poorly phosphorylated at its phosphoacceptor Asp
in vitro
. This phosphorylation, however, enhanced MaeR binding
in vitro
to its target sites and it was required for induction of regulated genes
in vivo
. Elucidation of the MaeR structure revealed that response regulator dimerization is accomplished by the swapping of α4-β5-α5 elements between two monomers, generating a phosphoacceptor competent conformation. Sequence and phylogenetic analyses showed that the MaeKR peculiarities are not exclusive to
L. casei
as they are shared by the rest of orthologous systems of
Lactobacillales
. Our results reveal MaeKR as a non-canonical TCS displaying distinctive features: a swapped response regulator and a sensor histidine kinase lacking ATP-dependent kinase activity. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 2045-2322 2045-2322 |
DOI: | 10.1038/s41598-017-02900-z |