Takamune K, Nishida H, Takai M, Katagiri C
Zoological Institute, Faculty of Science, Hokkaido University, Sapporo, Japan.
Eur J Biochem. 1991 Mar 14;196(2):401-6. doi: 10.1111/j.1432-1033.1991.tb15830.x.
Acid extract of mature sperm of the toad, Bufo japonicus, exclusively comprised sperm-specific basic proteins which moved faster than somatic histones on acid/urea/Triton X-100 polyacrylamide gel electrophoresis. When these proteins were purified by reversed-phase high-performance liquid chromatography they were found to consist of three components; one of these was a phosphorylated form of another, so that there were only two distinct components (P1 and P2). Amino acid sequence analyses indicated that the components both contained 39 amino acid residues, with 43.6% Arg, and differed only in the 28th amino acid residue (P1, Asp; P2, Glu). They had molecular masses of 5092 Da (P1) and 5106 Da (P2). The nucleotide sequences of cDNA clones encoding P1 (245 bases) and P2 (305 bases) showed that the difference in the amino acid residue between P1 and P2 was due to the difference of a nucleotide at position +87. Both cDNAs possessed a canonical signal (AATAAA) for polyadenylation and/or cleavage of transcript at the 3' untranslational region. Statistical analyses of amino acid sequence similarities suggested that the Bufo protamines are homologous with the protamines of fishes rather than with those of avian/mammalians.
日本蟾蜍成熟精子的酸性提取物仅包含精子特异性碱性蛋白，在酸性/尿素/Triton X-100聚丙烯酰胺凝胶电泳中，这些蛋白的迁移速度比体细胞组蛋白快。当通过反相高效液相色谱法纯化这些蛋白时，发现它们由三个组分组成；其中一个是另一个的磷酸化形式，因此只有两个不同的组分（P1和P2）。氨基酸序列分析表明，这两个组分均含有39个氨基酸残基，精氨酸含量为43.6%，仅在第28个氨基酸残基上有所不同（P1为天冬氨酸；P2为谷氨酸）。它们的分子量分别为5092 Da（P1）和5106 Da（P2）。编码P1（245个碱基）和P2（305个碱基）的cDNA克隆的核苷酸序列表明，P1和P2氨基酸残基的差异是由于第87位核苷酸的差异所致。两个cDNA在3'非翻译区均具有多聚腺苷酸化和/或转录本切割的典型信号（AATAAA）。氨基酸序列相似性的统计分析表明，蟾蜍鱼精蛋白与鱼类的鱼精蛋白同源，而不是与鸟类/哺乳动物的同源。
