Egyhazi E, Stigare J, Holst M, Pigon A
Department of Medical Cell Biology, Karolinska Institute, Stockholm, Sweden.
Mol Biol Rep. 1991 May;15(2):65-72. doi: 10.1007/BF00364841.
A structural homology is established between three DNA-binding phosphoproteins located in the 42 to 44 kDa range, referred to as pp42, pp43 and pp44, from Chironomus tentans salivary gland cells by in situ peptide mapping. The staining patterns of pp42, pp43 and pp44 which resulted from digestion with Staphylococcus aureus V8, trypsin or papain proteases show the presence of 8 to 15 spots majority of which have identical mobility. In the patterns of the digests generated by treatments with trypsin about 10 spots appear in common between any pair of the protein substrates. In addition, each pattern includes two to three peptides of mobility not present in the other. Thus the peptide mapping of pp42, pp43 and pp44 based on the staining patterns of proteolytic digests suggest the existence of structural homology between the three unlabelled substrates. The proteolytic peptides carrying the rapidly turning over phosphate groups form markedly different electrophoretic patterns than the unlabelled peptides visualized by staining. Treatment of 32P-labelled pp42, pp43 and pp44 with V8 generates only one labelled fragment in the 30 kD range. The cleavage patterns of pp44 produced by chymotrypsin or papain contain seven to ten labelled fragments while those of pp42 and pp43 contain only two. The 32P-labelled tryptic peptides of pp42, pp43 and pp44 exhibit a ladder pattern for each substrate which probably arise by a consecutive removal of 25 to 35 amino acid residues from the primary digestion products pp29, pp29.5 and pp30 by cleavage of four to five putative interdomain regions. The possibility that these three structurally related phosphoproteins belong to the category of transcription factors is discussed.
通过原位肽图谱分析，在来自摇蚊唾液腺细胞的分子量范围为42至44 kDa的三种DNA结合磷蛋白（称为pp42、pp43和pp44）之间建立了结构同源性。用金黄色葡萄球菌V8蛋白酶、胰蛋白酶或木瓜蛋白酶消化产生的pp42、pp43和pp44的染色模式显示存在8至15个斑点，其中大多数具有相同的迁移率。在用胰蛋白酶处理产生的消化模式中，任意两种蛋白质底物之间大约有10个斑点是共同出现的。此外，每种模式还包括两到三个其他模式中不存在的迁移率的肽段。因此，基于蛋白水解消化产物的染色模式对pp42、pp43和pp44进行的肽图谱分析表明这三种未标记的底物之间存在结构同源性。携带快速周转磷酸基团的蛋白水解肽形成的电泳模式与通过染色可视化的未标记肽明显不同。用V8处理32P标记的pp42、pp43和pp44仅在30 kD范围内产生一个标记片段。胰凝乳蛋白酶或木瓜蛋白酶对pp44产生的切割模式包含7至10个标记片段，而pp42和pp43的切割模式仅包含2个。pp42、pp43和pp44的32P标记的胰蛋白酶肽段对每种底物都呈现出一种阶梯模式，这可能是由于从初级消化产物pp29、pp29.5和pp30中通过切割四到五个假定的结构域间区域连续去除25至35个氨基酸残基而产生的。本文讨论了这三种结构相关的磷蛋白属于转录因子类别的可能性。
