Dataset Information

Marine Proteobacteria metabolise glycolate via the β-hydroxyaspartate cycle

ABSTRACT: One of the most abundant organic carbon sources in the ocean is glycolate, a compound that is commonly secreted by marine phytoplankton resulting in an estimated annual flux of one petagram of glycolate in marine environments. While it is generally accepted that glycolate is oxidized to glyoxylate by marine bacteria, the further fate of this C2 metabolite is not well understood. Here we show that ubiquitous marine Proteobacteria are able to assimilate glyoxylate via the hydroxyaspartate cycle (BHAC) that was originally proposed 56 years ago. We unravel the biochemistry of the BHAC and describe the structure of its key enzymes, including a previously unknown primary imine reductase. Overall, the BHAC allows for the direct production of oxaloacetate from glyoxylate through only four enzymatic steps, representing the most efficient glyoxylate assimilation route described to date. Analysis of marine metagenomes shows that the BHAC is globally distributed and on average 20-fold more abundant than the glycerate pathway, the only other known pathway for net glyoxylate assimilation. In a field study on a phytoplankton bloom, we show that glycolate is present in high nanomolar concentrations and taken up by prokaryotes at rates that allow a full turnover of the glycolate pool within one week. During the bloom, the BHAC is present in up to 1.5% of the bacterial community and actively transcribed, supporting its role in glycolate assimilation and suggesting a new trophic interaction between autotrophic phytoplankton and heterotrophic bacterioplankton.

INSTRUMENT(S): Q Exactive

ORGANISM(S): Paracoccus Denitrificans Pd1222

TISSUE(S): Permanent Cell Line Cell, Cell Culture

SUBMITTER: Timo Glatter

LAB HEAD: Tobias Juergen Erb

PROVIDER: PXD013274 | Pride | 2019-10-14

REPOSITORIES: Pride

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Marine Proteobacteria metabolize glycolate via the β-hydroxyaspartate cycle.

Schada von Borzyskowski Lennart L Severi Francesca F Krüger Karen K Hermann Lucas L Gilardet Alexandre A Sippel Felix F Pommerenke Bianca B Claus Peter P Cortina Niña Socorro NS Glatter Timo T Zauner Stefan S Zarzycki Jan J Fuchs Bernhard M BM Bremer Erhard E Maier Uwe G UG Amann Rudolf I RI Erb Tobias J TJ

Nature 20191113 7783

One of the most abundant sources of organic carbon in the ocean is glycolate, the secretion of which by marine phytoplankton results in an estimated annual flux of one petagram of glycolate in marine environments1. Although it is generally accepted that glycolate is oxidized to glyoxylate by marine bacteria2-4, the further fate of this C2 metabolite is not well understood. Here we show that ubiquitous marine Proteobacteria are able to assimilate glyoxylate via th ...[more]

PMID: 31723261

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