Ishimi Y, Ichinose S, Omori A, Sato K, Kimura H
Mitsubishi Kasei Institute of Life Sciences, 11 Minamiooya, Machida, Tokyo 194, Japan.
J Biol Chem. 1996 Sep 27;271(39):24115-22. doi: 10.1074/jbc.271.39.24115.
Minichromosome maintenance (MCM) proteins play essential roles in eukaryotic DNA replication, but their biochemical properties remain to be determined. We detected in HeLa cell extracts six proteins, CDC47, CDC46/MCM5, Cdc21, P1/MCM3, Mis5, and BM28/MCM2, by their binding to a specific antibody and by partial sequencing. The human homologs of the MCM2 (BM28), Mis5, Cdc21, and CDC47 proteins were tightly bound to a histone-Sepharose column and purified to near homogeneity, whereas the P1/MCM3 and CDC46/MCM5 proteins passed through. Among the four core histones, the human BM28/MCM2, Mis5, Cdc21, and CDC47 proteins had high affinity for histone H3. Immunoprecipitation with anti-Cdc21 antibody revealed that these four MCM proteins form complexes. These results are consistent with the findings that MCM proteins bind with chromatin in vivo.
微小染色体维持（MCM）蛋白在真核生物DNA复制中起关键作用，但其生化特性仍有待确定。我们通过与特异性抗体结合及部分测序，在HeLa细胞提取物中检测到六种蛋白，即CDC47、CDC46/MCM5、Cdc21、P1/MCM3、Mis5和BM28/MCM2。MCM2（BM28）、Mis5、Cdc21和CDC47蛋白的人类同源物紧密结合于组蛋白-琼脂糖柱，并纯化至接近均一，而P1/MCM3和CDC46/MCM5蛋白则通过了该柱。在四种核心组蛋白中，人类BM28/MCM2、Mis5、Cdc21和CDC47蛋白对组蛋白H3具有高亲和力。用抗Cdc21抗体进行免疫沉淀显示，这四种MCM蛋白形成复合物。这些结果与MCM蛋白在体内与染色质结合的发现一致。
