Bunai K, Takamatsu H, Horinaka T, Oguro A, Nakamura K, Yamane K
Institute of Biological Sciences, University of Tsukuba, Ibaraki, Japan.
Biochem Biophys Res Commun. 1996 Oct 23;227(3):762-7. doi: 10.1006/bbrc.1996.1582.
We analyzed the binding activity of B. subtilis Ffh to the precursors of secretory proteins by purifying mature and precursor proteins of beta-lactamase derived from pUC18 and its derivatives, of which the signal peptide region was replaced with that of E. coli OmpA, B. subtilis AprE, PBP5* or an alkalophilic Bacillus sp. #1011 CGTase. Each of them was mixed with purified B. subtilis Ffh in the presence of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDAC). The tested precursor proteins, including those of E. coli, of which the signal sequences differ from those of B. subtilis in the number of charged amino acids and hydrophobicity, cross-linked with Ffh, whereas mature proteins did not. The addition of scRNA, the B. subtilis counterpart of mammalian SRP 7S RNA, into the mixture did not affect the complex formation. These findings suggest that B. subtilis Ffh intrinsically binds to several precursor proteins.
我们通过纯化源自pUC18及其衍生物的β-内酰胺酶的成熟蛋白和前体蛋白来分析枯草芽孢杆菌Ffh与分泌蛋白前体的结合活性，其中信号肽区域被大肠杆菌OmpA、枯草芽孢杆菌AprE、PBP5*或嗜碱芽孢杆菌#1011 CGTase的信号肽区域所取代。将它们各自在1-乙基-3-(3-二甲基氨基丙基)碳二亚胺(EDAC)存在的情况下与纯化的枯草芽孢杆菌Ffh混合。所测试的前体蛋白，包括那些信号序列在带电氨基酸数量和疏水性方面与枯草芽孢杆菌不同的大肠杆菌前体蛋白，与Ffh发生交联，而成熟蛋白则不会。向混合物中添加枯草芽孢杆菌对应于哺乳动物SRP 7S RNA的scRNA不会影响复合物的形成。这些发现表明枯草芽孢杆菌Ffh本质上与几种前体蛋白结合。
