METTL21C蛋白的序列特征、三维结构及分子进化

METTL21C蛋白作为甲基转移酶参与多种细胞进程的翻译后修饰,在生命活动中发挥重要的调控作用。从蛋白质信息数据库UniprotKB中选取36个不同代表物种的METTL21C蛋白作为研究对象,理化参数分析显示一级序列中氨基酸残基个数差异较大,平均为254个氨基酸残基,大多为偏酸亲水性蛋白。系统进化树显示36种METTL21C蛋白共分为哺乳类、爬行类、鸟类和鱼类4支,与物种的亲缘进化关系基本吻合。多序列比对和motif分析结果表明不同物种METTL21C蛋白的序列相似度较高,10个motif序列几乎覆盖了全长多肽链,大都含有motif 1～motif 5,但N端序列差异较大,在哺乳动物中包含特有的motif 7、motif 8和motif 10,而在多种鸟类中有大段序列缺失。结构对比分析发现不同物种METTL21C蛋白的空间构象绝大部分区域近乎完全重叠,仅少部分自由度较高的局部肽段有一定程度的差异,表明不同物种METTL21C在进化过程中一级序列有一定的差异,但是空间结构极为相似。以人METTL21C为蛋白质互作网络中心,直接相关蛋白质共11种,间接相关蛋白质共9种,说明METTL21C直接或间接参与多种细胞进程,调控机体的生命活动,为进一步深入研究METTL21C的生物学功能及其分子机制提供了理论基础。

Sequence Characterization,Three-dimensional Structure and Molecular Evolution of METTL21C Protein

As methyltransferase,METTL21C protein is involved in post-translational modification in a variety of cellular processes and plays a role of important regulative function in the life activities.With thirty-six METTL21C proteins from different representative species in universal protein database (UniprotKB) as research objects,after we analyzed the physical and chemical parameters,the results showed that the number of amino acid residues was various in primary sequences,and the average was 254 residues.Most of them were the acidic and hydrophilic proteins.The phylogenetic tree results indicated that 36 of METTL21C proteins were divided into four branches,including mammals,reptiles,birds and fishes.It was basically consistent with phylogenetic relationship of species.The results of multiple sequence alignment and motif analysis showed that METTL21C proteins from different species had high sequence similarity.Ten motifs sequences nearly covered the total length of polypeptide chains.Most of them contained motifs 1-5.However,there was a great difference in the N-terminal sequences.METTL21C proteins from mammals possessed their unique motifs 7,8 and 10,whereas a large segment of sequences in birds missed.The results of structure alignment revealed that conformations of METTL21C proteins from different species almost completely overlapped in most of region.A small amount of peptide fragments with higher freedom had a certain degree of difference.It was suggested that METTL21C from different species had certain difference in the primary sequence,but had similar conformation in spatial structure.Human METTL21C as a center in protein interaction network was directly related to 11 proteins and indirectly related to 9 proteins.So the METTL21C directly or indirectly involves in multiple cellular processes to regulate life activities of organisms.The research provides a theoretical basis for further study of the biological function as well as molecular mechanism of METTL21C.