Dierstein R, Wickner W
EMBO J. 1986 Feb;5(2):427-31. doi: 10.1002/j.1460-2075.1986.tb04228.x.
Many secreted and membrane proteins have amino-terminal leader peptides which are essential for their insertion across the membrane bilayer. These precursor proteins, whether from prokaryotic or eukaryotic sources, can be processed to their mature forms in vitro by bacterial leader peptidase. While different leader peptides have shared features, they do not share a unique sequence at the cleavage site. To examine the requirements for substrate recognition by leader peptidase, we have truncated M13 procoat, a membrane protein precursor, from both the amino- and carboxy-terminal ends with specific proteases or chemical cleavage agents. The fragments isolated from these reactions were assayed as substrates for leader peptidase. A 16 amino acid residue peptide which spans the leader peptidase cleavage site is accurately cleaved. Neither the basic amino-terminal region nor most of the hydrophobic central region of the leader peptide are essential for accurate cleavage.
许多分泌蛋白和膜蛋白都有氨基末端前导肽，这些前导肽对于它们跨膜双层插入至关重要。这些前体蛋白，无论来自原核生物还是真核生物来源，都可以在体外被细菌前导肽酶加工成成熟形式。虽然不同的前导肽有共同的特征，但它们在切割位点并没有共享独特的序列。为了研究前导肽酶识别底物的要求，我们用特定的蛋白酶或化学切割剂从氨基末端和羧基末端截断了膜蛋白前体M13原衣壳。从这些反应中分离出的片段作为前导肽酶的底物进行检测。跨越前导肽酶切割位点的一个16个氨基酸残基的肽被准确切割。前导肽的碱性氨基末端区域和大部分疏水中心区域对于准确切割都不是必需的。
