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- Title
Biochemical and molecular characterization of a lipase from an Algerian isolated Staphylococcus aureus strain.
- Authors
Nehal, Fatima; Jallouli, Raida; Krayem, Najeh; Bou Ali, Madiha; Dilmi Bouras, Abdelkader; Fendri, Ahmed; Gargouri, Youssef
- Abstract
A Staphylococcus aureus strain, isolated from an Algerian biotope, secretes a non-induced lipase in the culture medium. The S. aureus lipase (SAL) was purified to homogeneity. Pure SAL is a monomeric protein (43 kDa). The 20 N-terminal amino acid residues showed a high degree of homology with other staphylococcal lipase sequences. SAL presents specific activities of about 1600 and 555 U mg−1 using tributyrin and olive oil emulsion as substrates, respectively. In contrast to other staphylococcal lipases previously characterized, SAL was stable at a pH range from 6 to 9 after 1 h incubation, and retained 50% of its activity after 10 min incubation at 50 °C. The purified enzyme was also characterized using monolayer technique. Lipase activity can be measured only when the surface pressure exceeds 15 mN m−1. The critical surface pressure ( πc) measured with egg-PC films was estimated at 33 mN m−1. SAL showed a preference for the distal ester groups of the diglyceride isomers at low surface pressure, for the adjacent ester groups at high surface pressure and a preference for the sn-3 position of the 2,3- sn-enantiomer of dicaprin. Cloned and sequenced gene part, encoding the mature lipase shows, in comparison with S. aureus lipase 3 (SAL3), a deletion of three residues (LKA) at the N-terminal extremity and a substitution of glycine 208 and isoleucine 226 with an arginine and leucine, respectively.
- Subjects
LIPASE biotechnology; STAPHYLOCOCCUS aureus genetics; GENETICS of staphylococcus aureus infections; MOLECULAR structure of amino acids; TRIBUTYRIN
- Publication
Journal of Basic Microbiology, 2017, Vol 57, Issue 3, p253
- ISSN
0233-111X
- Publication type
Article
- DOI
10.1002/jobm.201600462