RRC ID 53603
Author Awai K, Ohta H, Sato N.
Title Oxygenic photosynthesis without galactolipids.
Journal Proc. Natl. Acad. Sci. U.S.A.
Abstract The thylakoid membranes of oxygenic photosynthetic organisms are dominated by the galactolipids monogalactosyldiacylglycerol (MGDG) and digalactosyldiacylglycerol (DGDG). In cyanobacteria, MGDG is synthesized via monoglucosyldiacylglycerol (GlcDG). However, the putative epimerase involved in the conversion of GlcDG to MGDG has not been identified. Here we report the identification of the gene for the glucolipid epimerase (mgdE) by comparative genomic analysis. Knockout mutants of mgdE in Synechocystis sp. PCC 6803 lacked both MGDG and DGDG and accumulated GlcDG. The mutants did possess thylakoid membranes and showed normal maximal photosynthetic activity, albeit with reduced utilization of light energy. These results cast doubt on the long-standing belief that oxygenic photosynthesis is absolutely dependent on galactolipids.
Volume 111(37)
Pages 13571-5
Published 2014-9-16
DOI 10.1073/pnas.1403708111
PII 1403708111
PMID 25197079
PMC PMC4169966
MeSH Escherichia coli / genetics Galactolipids / biosynthesis Galactolipids / chemistry Galactolipids / metabolism* Mutation / genetics Oxygen / metabolism* Photosynthesis* Phylogeny Racemases and Epimerases / metabolism Synechocystis / genetics Synechocystis / metabolism* Thylakoids / metabolism Thylakoids / ultrastructure
IF 9.504
Prokaryotes E. coli