Effect of enzymic methylation of heterogeneous ribonucleoprotein particle A1 on its nucleic-acid binding and controlled proteolysis.
Effect of enzymic methylation of heterogeneous ribonucleoprotein particle A1 on its nucleic-acid binding and controlled proteolysis.
复制标题
异源核糖核蛋白颗粒 A1 的酶甲基化对其核酸结合和受控蛋白水解的影响。
DOI：
10.1042/bj3040903
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发表时间：
1994
期刊：
影响因子：
--
通讯作者：
Kim,S
中科院分区：
文献类型：
--
作者：
Rajpurohit,R;Paik,WK;Kim,S
重组非甲基化异质核糖核蛋白(HnRNP)蛋白A1由核蛋白/组蛋白甲基化酶I[RajpuroHit，Lee，Park，Paik和Kim(1994)J.Biol]催化甲基化。化学。269,1057-1082]，并研究了甲基化对几种理化性质的影响。甲基化和未甲基化的蛋白A1与核酸的相对结合亲和力有很大的不同。这通过蛋白质A1在单链DNA/纤维素柱上的洗脱行为观察到；释放结合蛋白A1所需的氯化钠浓度分别为0.59M(甲基化)和0.63M(非甲基化)。通过等电聚焦，甲基化和未甲基化蛋白质的等电点分别为9.41和9.48。在大肠杆菌噬菌体MS2-RNA存在的情况下，蛋白质A1的最大荧光猝灭在甲基化时为40%，而在未甲基化时为45%。当两种蛋白A1在受控胰酶消化时，甲基化蛋白的t1/2为1.31min，未甲基化蛋白为1.63min。在有MS2-RNA存在的情况下，它们的t1/2值相差很大，前者为2.4min，后者为4.3min，表明甲基化物种比未甲基化的物种更不稳定。所有上述结果一致表明，hnRNP蛋白A1在精氨酸甲基化后与单链核酸的结合性能显著降低。讨论了这一观测的生物学意义。
Recombinant unmethylated heterogeneous nuclear ribonucleoprotein particle (hnRNP) protein A1 was enzymatically methylated by nuclear protein/histone protein methylase I [Rajpurohit, Lee, Park, Paik and Kim (1994) J. Biol. Chem. 269, 1057-1082] and the effect of methylation on several physiocochemical properties was studied. The relative binding-affinity of methylated and unmethylated protein A1 to nucleic acid was quite different. This was observed by the elution behaviour of the protein A1 on a single-stranded DNA/cellulose column; the concentration of NaCl required to release the bound protein A1 was 0.59 M for the methylated and 0.63 M for the unmethylated, respectively. Employing isoelectrofocusing, pI values of the methylated and unmethylated proteins were found to be 9.41 and 9.48, respectively. Maximum fluorescence quenching of protein A1 in the presence of coliphage MS2-RNA was found to be 40% with methylated and 45% with unmethylated. When both species of protein A1 were subjected to controlled trypsin digestion, t1/2 of the methylated protein was 1.31 min and the unmethylated, 1.63 min. The difference in their t1/2 values was much greater in the presence of MS2-RNA; 2.4 min for the former and 4.3 min for the latter, indicating that the methylated species was less stabilized by the RNA than the unmethylated. All of the above results consistently suggested that the binding-property of hnRNP protein A1 to single-stranded nucleic acid was significantly reduced subsequent to its arginine-methylation. The biological significance of this observation is discussed.