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Three-dimensional structure and organization of a receptor/signaling complex
被引:54
作者:
Francis, NR
Wolanin, PM
Stock, JB
DeRosier, DJ
Thomas, DR
[1
]
机构:
[1] Princeton Univ, Dept Mol Biol, Princeton, NJ 08544 USA
[2] Brandeis Univ, Rosenstiel Biomed Sci Res Ctr, Waltham, MA 02454 USA
[3] Princeton Univ, Dept Mol Biol, Princeton, NJ 08544 USA
[4] Princeton Univ, Dept Chem, Princeton, NJ 08544 USA
来源:
关键词:
chemotaxis;
electron microscopy;
macromolecular assembly;
signal transduction;
D O I:
10.1073/pnas.0407826101
中图分类号:
O [数理科学和化学];
P [天文学、地球科学];
Q [生物科学];
N [自然科学总论];
学科分类号:
07 ;
0710 ;
09 ;
摘要:
Transmembrane signaling in bacterial chemotaxis has become an important model system for experimental and theoretical studies. These studies have provided a wealth of detailed molecular structures, including the structures of CheA, CheW, and the cytoplasmic domain of the serine receptor Tsr. How these three proteins interact to form the receptor/signaling complex remains unknown. By using EM and single-particle image analysis, we present a three-dimensional reconstruction of the receptor/signaling complex. The complex contains CheA, CheW, and the cytoplasmic portion of the aspartate receptor Tar. We observe density consistent with a structure containing 24 aspartate-receptor monomers and additional density sufficient to house the expected four CheA monomers and six CheW monomers. Within this bipolar structure are four groups of three receptor dimers that are not threefold symmetric and are therefore unlike the symmetric trimers observed in the x-ray crystal structure of the cytoplasmic domain of the serine receptor. In the latter, the interdimer contacts occur in the signaling domains near the hairpin loop. In our structure, the signaling domains within trimers appear spaced apart by the presence of CheA and CheW. This structure argues against models where one CheA and one CheW bind to the outer face of each of the dimers in the trimer. This structure of the receptor/signaling complex provides an additional basis for understanding the architecture of the large arrays of chemotaxis receptors, CheA, and CheW found at the cell poles in motile bacteria.
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页码:17480 / 17485
页数:6
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