Molecular and Structural Characterizations of Lipases from <i>Chlorella</i> by Functional Genomics
Hajer Ben Hlima,
Mouna Dammak,
Aida Karray,
Maroua Drira,
Philippe Michaud,
Imen Fendri,
Slim Abdelkafi
Affiliations
Hajer Ben Hlima
Laboratoire de Génie Enzymatique et de Microbiologie, Equipe de Biotechnologie des Algues, Ecole Nationale d’Ingénieurs de Sfax, Université de Sfax, Sfax 3038, Tunisia
Mouna Dammak
Laboratoire de Génie Enzymatique et de Microbiologie, Equipe de Biotechnologie des Algues, Ecole Nationale d’Ingénieurs de Sfax, Université de Sfax, Sfax 3038, Tunisia
Aida Karray
Laboratoire de Biochimie et de Génie Enzymatique des Lipases, Ecole Nationale d’Ingénieurs de Sfax, Université de Sfax, Sfax 3038, Tunisia
Maroua Drira
Laboratoire de Biotechnologie Végétale Appliquée à l’Amélioration des Cultures, Faculté des Sciences de Sfax, Université de Sfax, Sfax 3038, Tunisia
Philippe Michaud
CNRS, SIGMA Clermont, Institut Pascal, Université Clermont-Auvergne, F-63000 Clermont-Ferrand, France
Imen Fendri
Laboratoire de Biotechnologie Végétale Appliquée à l’Amélioration des Cultures, Faculté des Sciences de Sfax, Université de Sfax, Sfax 3038, Tunisia
Slim Abdelkafi
Laboratoire de Génie Enzymatique et de Microbiologie, Equipe de Biotechnologie des Algues, Ecole Nationale d’Ingénieurs de Sfax, Université de Sfax, Sfax 3038, Tunisia
Microalgae have been poorly investigated for new-lipolytic enzymes of biotechnological interest. In silico study combining analysis of sequences homologies and bioinformatic tools allowed the identification and preliminary characterization of 14 putative lipases expressed by Chlorella vulagaris. These proteins have different molecular weights, subcellular localizations, low instability index range and at least 40% of sequence identity with other microalgal lipases. Sequence comparison indicated that the catalytic triad corresponded to residues Ser, Asp and His, with the nucleophilic residue Ser positioned within the consensus GXSXG pentapeptide. 3D models were generated using different approaches and templates and demonstrated that these putative enzymes share a similar core with common α/β hydrolases fold belonging to family 3 lipases and class GX. Six lipases were predicted to have a transmembrane domain and a lysosomal acid lipase was identified. A similar mammalian enzyme plays an important role in breaking down cholesteryl esters and triglycerides and its deficiency causes serious digestive problems in human. More structural insight would provide important information on the enzyme characteristics.
