Barbosa M S, Lowy D R, Schiller J T
Laboratory of Cellular Oncology, National Cancer Institute, Bethesda, Maryland 20892.
J Virol. 1989 Mar;63(3):1404-7. doi: 10.1128/JVI.63.3.1404-1407.1989.
Papillomavirus proteins E6 and E7 have Cys-X-X-Cys repeats which have been suggested to mediate zinc binding. We have developed a modification of an assay that detects zinc binding to proteins immobilized on filters. Using well-characterized metalloproteins, we show that, under reducing conditions, this assay distinguishes proteins that coordinate zinc through cysteine residues from those that bind the metal through other amino acids. Under these conditions, E6 and E7 polypeptides of human papillomavirus type 18 and bovine papillomavirus type 1 exhibited high-affinity zinc binding. Our results suggest that E6 and E7 are metalloproteins and may coordinate the metal ions through cysteine residues.
乳头瘤病毒蛋白E6和E7含有Cys-X-X-Cys重复序列，有人认为该序列介导锌的结合。我们改进了一种检测锌与固定在滤膜上的蛋白质结合的分析方法。通过使用特性明确的金属蛋白，我们发现，在还原条件下，该分析方法能够区分通过半胱氨酸残基配位结合锌的蛋白质和通过其他氨基酸结合金属的蛋白质。在这些条件下，18型人乳头瘤病毒和1型牛乳头瘤病毒的E6和E7多肽表现出高亲和力的锌结合。我们的结果表明，E6和E7是金属蛋白，可能通过半胱氨酸残基配位结合金属离子。
