Clone And Analysis Of The CDNA Of LPL On Tianfu Meat Goose And The Phylogenetic Relationship In The Lipase Superfamily

Lipoprotein lipase(LPL) is a key enzyme in lipid metabolism. The total RNA was extracted from the lag muscle tissue of Tianfu Meat Goose and the partial sequence was cloned by the RT-PCR. LPL's structure and the mutation points were studied in order to discuss the function of domains and phylogenetic relationships of the lipase superfamily. The conclusions were summed up as the following:1. The length of the cloned sequence was 879 base pair which was induced to 293 amino acid residues. High similarity was found with the chicken's proportional mRNA sequence by 92.38％and other species.2. Twenty kinds of amino acids were found in the Tianfu Meat Goose's LPL sequence and the proportion of leucine was highest(8.90％), and lysine was second highest(7.88％), and the tryptophan(1.37％) and methionine (1.74％) were lowest. There were 13 mutational sites between the Tianfu Meat Goose's LPL sequence and the chicken's and the proportion was 4.44％. And 91 mutational sites were found between the Tianfu Meat Goose's LPL sequence and mammalian. The number of the Singleton variable sites was 44 and the proportion was 48.35％.3. The secondary structure was predicted and it was indicated that theα-helix had a proportion of 31.85％in the LPL amino acid sequence of the Tianfu Meat Goose, and the proportions of Extended strand and Random coil were 20.89％and 47.26％respectively, which composed of the secondary structure of the LPL together.4. There were four disulfide bonds, three N-linked glycosylation sites, one heparin-binding site, one lipase catalytic triad site, one lipid-binding site, one inducing site binding lipoprotein to LDL receptor, one PLAT domain, and one essential motif for dimerization in LPL of the Tianfu Meat Goose. This was consistent with other scholors' essays.5. The phylogenetic analysis of the lipase superfamily demonstrated that the lipoprotein lipase(LPL), endothelial lipase(EL), hepatic lipase(HL), pancreatic lipase (PL), and phosphatidylserine phospholipase Al(PLA1) were derived from a common ancestral gene for their high amino acid sequences' similarity. The phylogenetic development tree of the lipase superfamily was diverged into two lineages, or branches which were the LPL-EL-HL lineages and the PL-PLA1 lineages. It was revealed that LPL, EL, and the HL had a more close relative relationship than PL and PLA1. And PL and PLA1 were diverged later with each other.