Comparison of the Lipophosphoglycan 3 Gene of the Lizard and Mammalian Leishmania: A Homology Modeling

Background: Lipophosphoglycan 3 (LPG3) is required for the LPG assembly, a well known virulent molecule. In this study, the LPG3 gene of the lizard and mammalian Leishmania species were cloned and sequenced. A three-dimensional structure (3D) for the target sequence was also predicted by comparative (homology) modeling. Materials and Methods: An optimization PCR amplification was performed on genomic DNA extracted from two species of Leishmania. The desired PCR products were then cloned and sequenced. In addition, a homology modeling was carried out in order to create three-dimensional structure of the Leishmania LPG3 using SWISS-MODEL server. Results: The GC-rich LPG3 gene of two species of Leishmania was successfully amplified using optimized PCR reaction consisting of betaine and 2-mercaptoethanol with bovine serum albumin and then cloned. Sequence alignment of LPG3 showed 95% identity between Leishmania infantum and lizard Leishmania. With regard to the three-dimensional structure prediction of the modeled sequence of Leishmania LPG3, the similarity was found in the molecular structure. Comparative analysis of functional motifs in the target sequence indicated three conserved domains and a putative C-terminal ER retention signal, as well as several post-translational modification sites. From phylogram, L. infantum was also found to be clustered with lizard Leishmania in the phylogenetic tree. Conclusion: It is suggested that the lizard Leishmania may be evolutionarily more close to L. infantum.