Hofsteenge J, Kieffer B, Matthies R, Hemmings B A, Stone S R
Friedrich Miescher Institut, Basel, Switzerland.
Biochemistry. 1988 Nov 15;27(23):8537-44. doi: 10.1021/bi00423a006.
The primary structure of the ribonuclease inhibitor from pig liver has been determined by amino acid sequence analysis. The N alpha-acetylated polypeptide chain of 456 amino acids consists of 15 homologous leucine-rich repeats, characterized by leucyl residues at constant positions. Two types of alternating repeats occur, 29 (A) and 28 (B) residues long. The degree of identity between repeats of a given type ranged from 25 to 60%. Only one deletion in the B-repeat was necessary to perfectly align the leucyl residues between the two repeats. Leucine-rich repeats have previously been found in four membrane-bound proteins and one extracellular protein, and their amphiphilic character suggested that they could be involved in membrane binding. Ribonuclease inhibitor is the first example of a cytoplasmic protein containing this type of repeat. It seems likely, therefore, that leucine-rich repeats can have functions other than forming membrane binding structures.
通过氨基酸序列分析确定了猪肝核糖核酸酶抑制剂的一级结构。由456个氨基酸组成的Nα-乙酰化多肽链包含15个同源的富含亮氨酸重复序列，其特征是在恒定位置存在亮氨酰残基。存在两种交替重复序列，长度分别为29个残基（A）和28个残基（B）。给定类型重复序列之间的同一性程度在25%至60%之间。B重复序列中只需一个缺失就能使两个重复序列之间的亮氨酰残基完美对齐。富含亮氨酸重复序列先前已在四种膜结合蛋白和一种细胞外蛋白中发现，其两亲性表明它们可能参与膜结合。核糖核酸酶抑制剂是含有这种重复序列的细胞质蛋白的首个例子。因此，富含亮氨酸重复序列似乎可能具有形成膜结合结构以外的其他功能。
