Comparative Study of the Molecular Characterization, Evolution, and Structure Modeling of Digestive Lipase Genes Reveals the Different Evolutionary Selection Between Mammals and Fishes.
Comparative Study of the Molecular Characterization, Evolution, and Structure Modeling of Digestive Lipase Genes Reveals the Different Evolutionary Selection Between Mammals and Fishes.
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DOI：
10.3389/fgene.2022.909091
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发表时间：
2022
影响因子：
3.7
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中科院分区：
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脊椎动物需要合适的脂肪酶来消化脂质，以满足能量和必需营养素的需求；然而，鱼类的主要消化脂肪酶基因存在一定的争议。在这项研究中，在哺乳动物和鱼类中鉴定出了两种类型的消化脂肪酶基因（胰腺脂肪酶（pl）和胆汁盐激活脂肪酶（bsal））。这两个脂肪酶基因的邻近基因和关键活性位点在哺乳动物和鱼类中是保守的。在哺乳动物中发现了 3 个拷贝的 PL 基因，但在大多数鱼类中只发现了 1 个拷贝，并且在某些鱼类（例如斑马鱼、青鳉和鲤鱼）中甚至完全不存在 pl 基因。此外，对胰脂肪酶活性很重要的疏水性氨基酸残基（Ile 和 Leu）在大多数鱼类中也不存在。 PL是哺乳动物中主要的消化脂肪酶基因，但由于pl基因序列和重要氨基酸残基的缺失，pl基因似乎不是鱼类中的主要消化脂肪酶基因。相比之下，bsal基因存在于所有鱼类中，甚至在大多数鱼类中发现了2到5个拷贝的bsal基因，但在哺乳动物中只发现了1个拷贝的BSAL基因。胆汁盐结合位点的氨基酸残基和Bsal蛋白的三维（3D）结构模型在大多数鱼类中都是保守的，因此bsal可能是鱼类主要的消化脂肪酶基因。系统发育分析还表明pl或bsal在哺乳动物和鱼类之间表现出独立进化。因此，我们推测哺乳动物和鱼类主要消化脂肪酶基因的进化选择分为两种类型。这些发现将为鱼类脂质消化的研究提供有价值的证据。
Vertebrates need suitable lipases to digest lipids for the requirement of energy and essential nutrients; however, the main digestive lipase genes of fishes have certain controversies. In this study, two types of digestive lipase genes (pancreatic lipase (pl) and bile salt-activated lipase (bsal)) were identified in mammals and fishes. The neighborhood genes and key active sites of the two lipase genes were conserved in mammals and fishes. Three copies of PL genes were found in mammals, but only one copy of the pl gene was found in most of the fish species, and the pl gene was even completely absent in some fish species (e.g., zebrafish, medaka, and common carp). Additionally, the hydrophobic amino acid residues (Ile and Leu) which are important to pancreatic lipase activity were also absent in most of the fish species. The PL was the main digestive lipase gene in mammals, but the pl gene seemed not to be the main digestive lipase gene in fish due to the absence of the pl gene sequence and the important amino acid residues. In contrast, the bsal gene existed in all fish species, even two to five copies of bsal genes were found in most of the fishes, but only one copy of the BSAL gene was found in mammals. The amino acid residues of bile salt-binding sites and the three-dimensional (3D) structure modeling of Bsal proteins were conserved in most of the fish species, so bsal might be the main digestive lipase gene in fish. The phylogenetic analysis also indicated that pl or bsal showed an independent evolution between mammals and fishes. Therefore, we inferred that the evolutionary selection of the main digestive lipase genes diverged into two types between mammals and fishes. These findings will provide valuable evidence for the study of lipid digestion in fish.