Structure elucidation of Staphylococcus capitis lipase. Molecular dynamics simulations to investigate the effects of calcium and zinc ions on the structural stability

Cold-adapted and organic solvent tolerant lipases have significant potential in a wide range of synthetic reactions in industry. But there are no sufficient studies on how these enzymes interacts with their substrates. Herein, the predicted structure and function of the Staphylococcus capitis lipase (SCL) are studied. Given the high amino acid sequence homology with the Staphylococcus simulans lipase (SSL), 3D structure models of closed and open forms of the S. capitis lipase were built using the structure of SSL as template. The models suggested the presence of a main lid and a second lid that may act with the former as a double door to control the access to the active site. The SCL models also allowed us to identify key residues involved in binding substrates, calcium or zinc ions. By following this model and utilizing molecular dynamics (MD) simulations, the stability of the S. capitis lipase at low temperatures could be explained in the presence and in the absence of calcium and zinc. Due to its thermolability, the SCL is extremely valuable for different biotechnological applications in a wide variety of industries from molecular biology to detergency to food and beverage preparation.Communicated by Ramaswamy H. Sarma.