Rolland N, Janosi L, Block M A, Shuda M, Teyssier E, Miège C, Chéniclet C, Carde J P, Kaji A, Joyard J
Laboratoire de Physiologie Cellulaire Végétale, Unité de Recherche Associée 576, 33405 Talence Cedex, France.
Proc Natl Acad Sci U S A. 1999 May 11;96(10):5464-9. doi: 10.1073/pnas.96.10.5464.
We have isolated a protein, mature RRFHCP, from chloroplasts of spinach (Spinacia oleracea L.) that shows 46% sequence identity and 66% sequence homology with ribosome recycling factor (RRF) of Escherichia coli. RRF recycles ribosomes through disassembly of the posttermination complex. From the cDNA analysis and from the amino-terminal sequencing of the isolated protein, the mature RRFHCP was deduced to have a Mr of 21,838 with 193 aa. It lacks the 78-aa chloroplast targeting sequence encoded by the RRFHCP cDNA sequence. The RRFHCP synthesized in vitro was imported into isolated chloroplasts with simultaneous conversion to the mature RRFHCP. Transcription of the gene coding for RRFHCP was not dependent on light, yet it was limited mostly to photosynthetic tissues in which only one transcript size was detected. Mature RRFHCP exerted a bactericidal effect on E. coli carrying temperature-sensitive RRF at the permissive temperature whereas wild-type E. coli was not affected.
我们从菠菜（Spinacia oleracea L.）叶绿体中分离出一种蛋白质——成熟的RRFHCP，它与大肠杆菌的核糖体循环因子（RRF）具有46%的序列同一性和66%的序列同源性。RRF通过拆解终止后复合物来循环利用核糖体。通过cDNA分析和对分离出的蛋白质进行氨基末端测序，推断成熟的RRFHCP的Mr为21,838，含有193个氨基酸。它缺少由RRFHCP cDNA序列编码的78个氨基酸的叶绿体靶向序列。体外合成的RRFHCP被导入分离的叶绿体中，并同时转化为成熟的RRFHCP。编码RRFHCP的基因转录不依赖于光，但主要局限于光合组织，在其中仅检测到一种转录本大小。成熟的RRFHCP在允许温度下对携带温度敏感型RRF的大肠杆菌具有杀菌作用，而野生型大肠杆菌不受影响。
