Bacillus subtilis histone-like protein, HBsu, is an integral component of a SRP-like particle that can bind the Alu domain of small cytoplasmic RNA
Bacillus subtilis histone-like protein, HBsu, is an integral component of a SRP-like particle that can bind the Alu domain of small cytoplasmic RNA
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DOI：
10.1074/jbc.274.19.13569
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发表时间：
1999-05-07
影响因子：
4.8
通讯作者：
Yamane, K
中科院分区：
文献类型：
--
作者：
Nakamura, K;Yahagi, S;Yamane, K
枯草杆菌小分子胞质RNA(ScRNA)在枯草杆菌细胞中代谢稳定，含量丰富。它由271个核苷酸组成，在结构上与哺乳动物信号识别颗粒RNA同源。枯草杆菌单链RNA含有进化上保守的S结构域，而不同于大肠杆菌的4.5GyaRNA。在这项研究中，我们证明了枯草杆菌细胞提取物中的10 kDa蛋白在ABU结构域具有scRNA结合活性。10-kDa蛋白的体外结合选择性表明，它识别由两个环中连续5个互补序列引起的scRNA的Alu结构域的较高结构。纯化和随后的分析表明，该10 kDa蛋白是HBsu，最初被鉴定为组蛋白样蛋白家族的成员。通过构建HBsu缺失的B，subtilis突变体，我们证明了HBsu是正常生长所必需的。用抗HBsu抗体免疫沉淀细胞裂解物可产生scRNA。此外，(His)(6)标记的FFH与HBsu的EO沉淀依赖于scRNA的存在，这表明HBsu、FFH和scRNA形成一个三元络合物，scRNA是一个结合的功能单位。这些结果表明，HBsu是枯草杆菌中能够与scRNA的Alu结构域结合的信号识别颗粒状颗粒的第三组分。
Small cytoplasmic RNA (scRNA) is metabolically stable and abundant in Bacillus subtilis cells. Consisting of 271 nucleotides, it is structurally homologous to mammalian signal recognition particle RNA. In contrast to 4.5 S RNA of Escherichia coli, B. subtilis scRNA contains an Alu domain in addition to the evolutionarily conserved S domain. In this study, we show that a 10-kDa protein in B, subtilis cell extracts has scRNA binding activity at the Abu domain. The in vitro binding selectivity of the 10-kDa protein shows that it recognizes the higher structure of the Alu domain of scRNA caused by five consecutive complementary sequences in the two loops. Purification and subsequent analyses demonstrated that the 10-kDa protein is HBsu, which was originally identified as a member of the histone-like protein family. By constructing a HBsu-deficient B, subtilis mutant, we showed that HBsu is essential for normal growth. Immunoprecipitating cell lysates using anti-HBsu antibody yielded scRNA. Moreover, the eo-precipitation of HBsu with (His)(6)-tagged Ffh depended on the presence of scRNA, suggesting that HBsu, Ffh, and scRNA make a ternary complex and that scRNA serves as a functional unit for binding. These results demonstrated that HBsu is the third component of a signal recognition particle-like particle in B, subtilis that can bind the Alu domain of scRNA.