Zhao W, Beintema J J, Hofsteenge J, Nevo E
Biochemisch Laboratorium, Rijksuniversiteit Groningen, The Netherlands.
Mol Phylogenet Evol. 1993 Sep;2(3):270-3. doi: 10.1006/mpev.1993.1025.
The primary structure of pancreatic ribonuclease of the superspecies Spalax leucodon has been determined. Only one difference with the previously determined sequence of the superspecies Spalax ehrenbergi was detected; the proline residue at position 42 has been replaced by alanine. Proline-42 is a well-conserved residue in mammalian pancreatic ribonucleases; the only other species with alanine at this position is the three-toed sloth. As the Muridae and the Spalacidae diverged 20-40 million years ago and the superspecies S. leucodon and S. ehrenbergi about 1-2 million years ago, and as pancreatic ribonuclease exhibits 24 substitutions in the line from the Muridae/Spalacidae ancestor to Spalax, a difference of one amino residue between the sequences of the two Spalax superspecies is what may be expected.
已确定了盲鼹属白齿盲鼹超种的胰腺核糖核酸酶的一级结构。与之前确定的盲鼹属埃氏盲鼹超种的序列相比，仅检测到一处差异；第42位的脯氨酸残基被丙氨酸取代。脯氨酸-42是哺乳动物胰腺核糖核酸酶中一个高度保守的残基；在这个位置上有丙氨酸的唯一其他物种是三趾树懒。由于鼠科和鼹形鼠科在2000万至4000万年前分化，而白齿盲鼹超种和埃氏盲鼹超种约在100万至200万年前分化，并且由于从鼠科/鼹形鼠科祖先到盲鼹的谱系中胰腺核糖核酸酶有24处替换，因此两个盲鼹超种序列之间有一个氨基酸残基的差异是可以预料的。
