Isolation and analysis of a gene from the marine microalga Isochrysis galbana that encodes a lipase-like protein

Microalgae constitute a novel study area for characterising new lipolytic enzymes of biotechnological interest. A new gene from the microalga Isochrysis galbana has been isolated and a preliminary characterisation performed. The full-length cDNA contains 2,060 base pairs with an open reading frame of 1,374 nucleotides encoding a polypeptide of 457 amino acids with a predicted molecular mass of 49 kDa, and a theoretical pI of 5.65. The deduced protein includes highly conserved motifs found in α/β fold hydrolases, and shares some similarities with putative or known lipases. Sequence comparison indicated that the catalytic triad corresponds to residues Ser¹⁸⁸, Asp³⁰⁶ and His³⁹¹, with the nucleophilic residue Ser¹⁸⁸ positioned within the consensus G-X-S¹⁸⁸-X-G pentapeptide. Phylogenetic analyses established close relationships with fungal lipases and microalgal sequences.