A novel Delta acyl-lipid desaturase, DesC2, from cyanobacteria acts on fatty acids esterified to the sn-2 position of glycerolipids

• Published in: Biochemical journal 2006-09, Vol.398 (2), p.207-214
• Main Authors: Chintalapati, Suresh, Prakash, Jogadhenu Shyam Sunder, Gupta, Pratima, Ohtani, Shuji, Suzuki, Iwane, Sakamoto, Toshio, Murata, Norio, Shivaji, Sisinthy
• Format: Article
• Language: English
• Subjects: Cyanophyta; Nostoc; Synechocystis
• ISSN: 0264-6021
• DOI: 10.1042/BJ20060039

Acyl-lipid desaturases are enzymes that convert a C-C single bond into a C=C double bond in fatty acids that are esterified to membrane-bound glycerolipids. Four types of acyl-lipid desaturase, namely DesA, DesB, DesC, and DesD, acting at the Delta super(12), Delta super(15), Delta , and Delta positions of fatty acids respectively, have been characterized in cyanobacteria. These enzymes are specific for fatty acids bound to the sn-1 position of glycerolipids. In the present study, we have cloned two putative genes for a Delta desaturase, designated desC1 and desC2, from Nostoc species. The desC1 gene is highly similar to the desC gene that encodes a Delta desaturase that acts on C sub(18) fatty acids at the sn-1 position. Homologues of desC2 are found in genomes of cyanobacterial species in which Delta -desaturated fatty acids are esterified to the sn-2 position. Heterologous expression of the desC2 gene in Synechocystis sp. PCC 6803, in which a saturated fatty acid is found at the sn-2 position, revealed that DesC2 could desaturate this fatty acid at the sn-2 position. These results suggest that the desC2 gene is a novel gene for a Delta acyl-lipid desaturase that acts on fatty acids esterified to the sn-2 position of glycerolipids.