Laboratory of Phylogenomic Ecology, Institute of Molecular Biology, Slovak Academy of Sciences, Dúbravská cesta 21, SK-84551 Bratislava, Slovakia; Department of Inorganic Chemistry, Faculty of Natural Sciences, Comenius University Bratislava, Mlynská dolina, Ilkovičova 6, SK-84215 Bratislava, Slovakia.
Laboratory of Phylogenomic Ecology, Institute of Molecular Biology, Slovak Academy of Sciences, Dúbravská cesta 21, SK-84551 Bratislava, Slovakia.
Int J Biol Macromol. 2023 Dec 1;252:126537. doi: 10.1016/j.ijbiomac.2023.126537. Epub 2023 Aug 25.
Deep evolutionary origin of the conserved animal serum amyloid A (SAA) apolipoprotein family leading to yet unknown highly similar SAA-like sequences occurring in certain bacterial genomes is demonstrated in this contribution. Horizontal gene transfer event of corresponding genes between gut bacteria and non-vertebrate animals was discovered in the reconstructed phylogenetic tree obtained with maximum likelihood and neighbor-joining methods, respectively. This detailed phylogeny based on totally 128 complete sequences comprised diverse serum amyloid A isoforms from various animal vertebrate and non-vertebrate phyla and also corresponding genes coding for highly similar proteins from animal gut bacteria. Typical largely conserved sequence motifs and a peculiar structural fold consisting mainly of four α-helices in a bundle within all reconstructed clades of the SAA protein family are discussed with respect to their supposed biological functions in various organisms that contain corresponding genes.
本研究证明，保守的动物血清淀粉样蛋白 A（SAA）载脂蛋白家族具有深远的进化起源，导致某些细菌基因组中出现了尚未被充分了解的高度相似的 SAA 样序列。通过最大似然法和邻接法分别构建的重建系统发育树发现，相应的基因在肠道细菌和非脊椎动物之间发生了水平基因转移事件。该详细的系统发育树基于 128 个完整序列，包括来自各种动物门的不同血清淀粉样蛋白 A 同工型以及来自动物肠道细菌的高度相似蛋白质的相应基因。讨论了在 SAA 蛋白家族的所有重建分支中普遍存在的典型的高度保守序列基序和特殊的结构折叠，主要由四个α-螺旋组成的束，以及它们在包含相应基因的各种生物体中的潜在生物学功能。
