Format

Send to

Choose Destination
Proc Natl Acad Sci U S A. 2014 Sep 16;111(37):13571-5. doi: 10.1073/pnas.1403708111. Epub 2014 Sep 2.

Oxygenic photosynthesis without galactolipids.

Author information

1
Graduate School of Science, Shizuoka University, Shizuoka 422-8529, Japan; Research Institute of Electronics, Shizuoka University, Hamamatsu 432-8011, Japan; Precursory Research for Embryonic Science and Technology, Japan Science and Technology Agency, Kawaguchi 332-0012, Japan; dkawai@ipc.shizuoka.ac.jp.
2
Center for Biological Resources and Informatics, Tokyo Institute of Technology, Yokohama 226-8501, Japan; Earth-Life Science Institute, Tokyo Institute of Technology, Tokyo 152-8551, Japan; Core Research for Evolutional Science and Technology, Japan Science and Technology Agency, Tokyo 102-0076, Japan; and.
3
Core Research for Evolutional Science and Technology, Japan Science and Technology Agency, Tokyo 102-0076, Japan; and Department of Life Sciences, Graduate School of Arts and Sciences, University of Tokyo, Tokyo 153-8902, Japan.

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.

KEYWORDS:

NAD(P)H-dependent oxidoreductase; chromatophore; cluster analysis; endosymbiosis; evolution of photosynthesis

PMID:
25197079
PMCID:
PMC4169966
DOI:
10.1073/pnas.1403708111
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for HighWire Icon for PubMed Central
Loading ...
Support Center