Acyl plastoquinol is a major cyanobacterial substance that co-migrates with triacylglycerol in thin-layer chromatography

Various studies have suggested the presence of triacylglycerol in cyanobacteria, but no convincing evi-dence exists. We purified a substance co-migrating with triacylglycerol in thin-layer chromatography and determined its structure using mass spectrometry, gas chromatography, and 1H and 13C NMR. The major components were palmitoyl and stearoyl plastoquinols (acyl plastoquinol). Acyl plastoquinol has never been described before, although acyloxy derivative of plastoquione has been described as plastoquinone B. The level of acyl plastoquinol was 0.4% of the total lipids. We still do not have clear evidence for the presence of triacylglycerol. If present, the maximum triacylglycerol level must be at most 10% of acyl plastoquinol. The Synechocystis Slr2103 protein was suggested to synthesize triacylglycerol, but the product could be acyl plastoquinol. The possible roles of this novel compound in photosynthesis should be a new focus of research.(c) 2022 Elsevier Inc. All rights reserved.

Automated summary

This study determined the structure of acyl plastoquinol, a novel compound found in cyanobacteria, using mass spectrometry, gas chromatography, and NMR. The level of acyl plastoquinol in total lipids was very low, and there is still no clear evidence for the presence of triacylglycerol. The potential roles of this compound in photosynthesis should be further investigated.