Identification of a gene for glycolipid synthase by comparative genomic analysis of two types of cyanobacteria

Abstract

Monogalactosyldiacylglycerol (MGDG) is a typical lipid in oxygen evolving photosynthetic organisms and occupies over half of the lipids in thylakoid membrane of chloroplast and cyanobacteria. MGDG is, therefore, considered as an essential factor for photosynthetic apparatus. In fact, from crystal structure analysis, MGDG is found to associate with reaction center protein of PSI. Although genes for MGDG synthesis have been isolated from higher plants, no one could find the ortholog from the Cyanobacteria genome of which has been sequenced.
Recently, we reported that there are two pathways for MGDG synthesis (UDP-Glc and UDP-Gal dependent) in cyanobacteria and the activities are conserved between Synechocysitis PCC6803 and Anabaena PCC7120. We assumed that the genes for these activities were highly conserved in both cyanobacteria and identified the UDP-Glc dependent glycolipid synthase gene by comparative genomic analysis. In this presentation, we will report the strategy for the identification and discuss knock-out mutant of the gene.