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Molecular dissection of bacterial acrylate catabolism – unexpected links with dimethylsulfoniopropionate catabolism and dimethyl sulfide production
Author(s) -
Todd Jonathan D.,
Curson Andrew R. J.,
NikolaidouKatsaraidou Nefeli,
Brearley Charles A.,
Watmough Nicholas J.,
Chan Yohan,
Page Philip C. B.,
Sun Lei,
Johnston Andrew W. B.
Publication year - 2010
Publication title -
environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.954
H-Index - 188
eISSN - 1462-2920
pISSN - 1462-2912
DOI - 10.1111/j.1462-2920.2009.02071.x
Subject(s) - dimethylsulfoniopropionate , catabolite repression , catabolism , dimethyl sulfide , biochemistry , biology , propionate , acrylate , escherichia coli , alcohol dehydrogenase , dehydrogenase , sulfur , chemistry , metabolism , gene , organic chemistry , enzyme , mutant , ecology , monomer , phytoplankton , nutrient , polymer
Summary A bacterium in the genus Halomonas that grew on dimethylsulfoniopropionate (DMSP) or acrylate as sole carbon sources and that liberated the climate‐changing gas dimethyl sulfide in media containing DMSP was obtained from the phylloplane of the macroalga Ulva. We identified a cluster that contains genes specifically involved in DMSP catabolism ( dddD, dddT ) or in degrading acrylate ( acuN , acuK ) or that are required to break down both substrates ( dddC , dddA ). Using NMR and HPLC analyses to trace 13 C‐ or 14 C‐labelled acrylate and DMSP in strains of Escherichia coli with various combinations of cloned ddd and/or acu genes, we deduced that DMSP is imported by the BCCT‐type transporter DddT, then converted by DddD to 3‐OH‐propionate (3HP), liberating dimethyl sulfide in the process. As DddD is a predicted acyl CoA transferase, there may be an earlier, unidentified catabolite of DMSP. Acrylate is also converted to 3HP, via a CoA transferase (AcuN) and a hydratase (AcuK). The 3HP is predicted to be catabolized by an alcohol dehydrogenase, DddA, to malonate semialdehyde, thence by an aldehyde dehydrogenase, DddC, to acyl CoA plus CO 2 . The regulation of the ddd and acu genes is unusual, as a catabolite, 3HP, was a co‐inducer of their transcription. This first description of genes involved in acrylate catabolism in any organism shows that the relationship between the catabolic pathways of acrylate and DMSP differs from that which had been suggested in other bacteria.