The role of C-terminal amino acid residues of a Δ⁶-fatty acid desaturase from blackcurrant.
Δ⁶-fatty acid desaturase is an important enzyme in the catalytic synthesis of polyunsaturated fatty acids. Using domain swapping and a site-directed mutagenesis strategy, we found that the region of the C-terminal 67 amino acid residues of Δ⁶-fatty acid desaturase RnD6C from blackcurrant was essential for its catalytic activity and that seven different residues between RnD6C and RnD8A in that region were involved in the desaturase activity. Compared with RnD6C, the activity of the following mutations, V394A, K395I, F411L, S436P, VK3945AI and IS4356VP, was significantly decreased, whereas the activity of I417T was significantly increased. The amino acids N, T and Y in the last four residues also play a certain role in the desaturase activity.
Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China. lysong@genetics.ac.cn
Li-Ying
LY
Song
Wan-Xiang
WX
Lu
Jun
J
Hu
Wei-Bo
WB
Yin
Yu-Hong
YH
Chen
Bai-Lin
BL
Wang
Richard R-C
RR
Wang
Zan-Min
ZM
Hu
D000595:Amino Acid Sequence; D050602:Linoleoyl-CoA Desaturase / Q000737:chemistry* / Q000235:genetics; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009154:Mutation; D010940:Plant Proteins / Q000737:chemistry* / Q000235:genetics; D017434:Protein Structure, Tertiary; D031965:Ribes / Q000201:enzymology*
D010940:Plant Proteins; D050602:Linoleoyl-CoA Desaturase