Abstract
Most extant cyanobacteria contain almost exclusively C16-fatty acids in the sn-2 positions of glycerolipids, which is under control of lysophosphatidic acid acyltransferases (LPAAT, EC 2.3.1.51). Synechocystis sp. PCC6803 contains sll1848, sll1752 and slr2060 for putative acyltransferase genes and C16 fatty acids in the sn-2 positions of glycerolipids are under control of sll1848. Here, we showed that Δ1848 Δ2060 cells extensively increase C18-fatty acids in the sn-2 positions, and decrease unsaturated C18-fatty acids in the sn-1 positions. Δ1848 Δ2060 cells showed a slow growth at 30 oC relative to the wild type and were sensitive to low temperature. sll1752 was upregulated in Δ1848 Δ2060 cells, where stearoyl-dependent LPAAT activity was also increased. Furthermore, LPAAT assays with recombinant proteins and growth complementation of Escherichia coli plsC cells verified that sll1752 encodes stearoyl-specific LPAAT. We conclude that sll1752 is sufficient but not preferable in the photosynthetic growth of this cyanobacterium.
