Two clusters of residues contribute to the activity and substrate specificity of Fm1, a bifunctional oleate and linoleate desaturase of fungal origin.

ABSTRACT: Polyunsaturated fatty acids (PUFAs) have important industrial, physiological, and nutritional properties. Plants use the sequential activities of FAD2 and FAD3 desaturases to convert 18:1Δ9 to the important PUFA 18:3Δ9,12,15, whereas the fungus Fusarium verticillioides 7600 uses the bifunctional desaturase Fm1 for both reactions. Here, we used a combination of sequence comparisons, structural modeling, and mutagenesis experiments to investigate Fm1's regioselectivity and identified two functionally relevant clusters of residues that contribute to Fm1 activity. We found that cluster I (Leu¹⁵³, Phe¹⁵⁷, and His¹⁹⁴), located near the catalytic iron ions, predominantly affects activity, whereas cluster II (Tyr²⁸⁰, His²⁸⁴, and Leu

SUBMITTER: Cai Y 

PROVIDER: S-EPMC6314118 | biostudies-literature | 2018 Dec

REPOSITORIES: biostudies-literature