Analysis of the Structure-stability Relationship of Cold-adapted Lipase PsLip1 from Homology Modeling

ABSTRACT

Two initial models of cold-adapted lipase PsLip1 have been constructed, based on homology with the bacterial lipases Chromobacterium viscosum(CvLip) and Pseudomonas cepacia(PcLip), whose X-ray structures have been solved and refined to high resolution. The mature polypeptide chains of these lipases have 84% similarity. The models of Mod1 and Mod2 have been compared with the tertiary structures of CvLip and PcLip, respectively, and analyzed in terms of stabilizing interactions. Several structural aspects that are believed to contribute to protein stability have been compared the number of conserved salt bridges, aromatic interactions, hydrogen bonds, helix capping, and disulfide bridges. The 3-dimensional structural model of PsLip1 has been constructed in order to elucidate the structural reasons for the decreased thermostability of the enzyme in comparison with its mesophilic counterparts.