Han Bong-Gyoon, Dong Ming, Liu Haichuan, Camp Lauren, Geller Jil, Singer Mary, Hazen Terry C, Choi Megan, Witkowska H Ewa, Ball David A, Typke Dieter, Downing Kenneth H, Shatsky Maxim, Brenner Steven E, Chandonia John-Marc, Biggin Mark D, Glaeser Robert M
Life Sciences, Genomics, Earth Sciences, and Physical Biosciences Divisions, Lawrence Berkeley National Laboratory, University of California, Berkeley, CA 94720, USA.
Proc Natl Acad Sci U S A. 2009 Sep 29;106(39):16580-5. doi: 10.1073/pnas.0813068106. Epub 2009 Sep 11.
An unbiased survey has been made of the stable, most abundant multi-protein complexes in Desulfovibrio vulgaris Hildenborough (DvH) that are larger than Mr approximately 400 k. The quaternary structures for 8 of the 16 complexes purified during this work were determined by single-particle reconstruction of negatively stained specimens, a success rate approximately 10 times greater than that of previous "proteomic" screens. In addition, the subunit compositions and stoichiometries of the remaining complexes were determined by biochemical methods. Our data show that the structures of only two of these large complexes, out of the 13 in this set that have recognizable functions, can be modeled with confidence based on the structures of known homologs. These results indicate that there is significantly greater variability in the way that homologous prokaryotic macromolecular complexes are assembled than has generally been appreciated. As a consequence, we suggest that relying solely on previously determined quaternary structures for homologous proteins may not be sufficient to properly understand their role in another cell of interest.
我们对希登伯勒脱硫弧菌（DvH）中稳定且含量最丰富的、分子量大于约400kDa的多蛋白复合物进行了无偏差调查。在这项工作中纯化的16种复合物中的8种的四级结构，通过对负染色标本进行单颗粒重建得以确定，成功率比之前的“蛋白质组学”筛选大约高10倍。此外，其余复合物的亚基组成和化学计量通过生化方法确定。我们的数据表明，在这一组具有可识别功能的13种大复合物中，只有两种的结构能够基于已知同源物的结构可靠地建模。这些结果表明，同源原核生物大分子复合物的组装方式存在的变异性比通常认为的要大得多。因此，我们认为仅依靠先前确定的同源蛋白质的四级结构可能不足以正确理解它们在另一个感兴趣的细胞中的作用。
