Russell W C, Webster A, Leith I R, Kemp G D
Department of Biochemistry and Microbiology, University of St Andrews, Fife, U.K.
J Gen Virol. 1989 Dec;70 ( Pt 12):3249-59. doi: 10.1099/0022-1317-70-12-3249.
Evidence is presented here which indicates that the adenovirus DNA-binding protein (DBP) is phosphorylated at a tyrosine residue early in infection. This was suggested by the discovery that a proportion of the label in 32P-labelled DBP was resistant to alkali, and was substantiated by acid hydrolysis of DBP immunoprecipitates and by immunoblotting with a monoclonal antibody against phosphotyrosine. Treatment of [35S]methionine-labelled DBPs with chymotrypsin produced fragments of apparent Mr 45K and 39K whereas digestion of 32P-labelled DBP resulted in fragments of 45K and 26K. Consideration of the distribution of 32P label and its alkali stability in these fragments suggested that chymotrypsin cleaved populations of DBP at different sites depending on their phosphorylation states. The conservation, in all of the seven adenovirus serotypes sequenced, of a tyrosine residue (at amino acid 195 in adenovirus type 2) together with its surrounding residues, suggests that phosphorylation/dephosphorylation at this tyrosine residue may be important in various functions ascribed to the DBP.
本文提供的证据表明，腺病毒DNA结合蛋白（DBP）在感染早期会在一个酪氨酸残基处发生磷酸化。这一推测源于以下发现：32P标记的DBP中一部分标记对碱具有抗性，通过对DBP免疫沉淀物进行酸水解以及使用抗磷酸酪氨酸单克隆抗体进行免疫印迹分析得到了证实。用胰凝乳蛋白酶处理[35S]甲硫氨酸标记的DBP会产生表观分子量为45K和39K的片段，而消化32P标记的DBP则会产生45K和26K的片段。对这些片段中32P标记的分布及其对碱的稳定性进行分析后表明，胰凝乳蛋白酶会根据DBP的磷酸化状态在不同位点切割DBP群体。在已测序的所有七种腺病毒血清型中，酪氨酸残基（腺病毒2型中的氨基酸195）及其周围残基的保守性表明，该酪氨酸残基处的磷酸化/去磷酸化可能在DBP的各种功能中起重要作用。
