Cloning, phylogenetic analysis and 3D modeling of a putative lysosomal acid lipase from the camel, Camelus dromedarius.

Acid lipase belongs to a family of enzymes that is mainly present in lysosomes of different organs and the stomach. It is characterized by its capacity to withstand acidic conditions while maintaining high lipolytic activity. We cloned for the first time the full coding sequence of camel's lysosomal acid lipase, cLIPA using RT-PCR technique (Genbank accession numbers JF803951 and AEG75815, for the nucleotide and aminoacid sequences respectively). The cDNA sequencing revealed an open reading frame of 1,197 nucleotides that encodes a protein of 399 aminoacids which was similar to that from other related mammalian species. Bioinformatic analysis was used to determine the aminoacid sequence, 3D structure and phylogeny of cLIPA. Bioinformatics analysis suggested the molecular weight of the translated protein to be 45.57 kDa, which could be decreased to 43.16 kDa after the removal of a signal peptide comprising the first 21 aminoacids. The deduced cLIPA sequences exhibited high identity with Equus caballus (86%), Numascus leucogenys (85%), Homo sapiens (84%), Sus scrofa (84%), Bos taurus (82%) and Ovis aries (81%). cLIPA shows high aminoacid sequence identity with human and dog-gastric lipases (58%, and 59% respectively) which makes it relevant to build a 3D structure model for cLIPA. The omparison confirms the presence of the catalytic triad and the oxyanion hole in cLIPA. Phylogenetic analysis revealed that camel cLIPA is grouped with monkey, human, pig, cow and goat. The level of expression of cLIPA in five camel tissues was examined using Real Time-PCR. The highest level of cLIPA transcript was found in the camel testis (162%), followed by spleen (129%), liver (100%), kidney (20.5%) and lung (17.4%).