2006 Fiscal Year Final Research Report Summary
Ligand-coupled allosteric phosphorylation of two-componetn system histidine kinases
| Project/Area Number |
17570123
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Functional biochemistry
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| Research Institution | RIKEN Institute |
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Principal Investigator |
NAKAMURA Hiro RIKEN Institute, Biometal Science, Senior Research Scientist, 城生体金属科学研究室, 先任研究員 (80270594)
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| Project Period (FY) |
2005 – 2006
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| Keywords | heme / kinase / sensor / membrane protein / pathogen / iron / histidine kinase / two-component system |
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| Research Abstract |
Iron is one of the most essential elements for living organisms. Pathogenic bacteria sequester heme irons from the bloods of the host. The chrS and chrA genes were discovered from Corynebacterium diphtheriae, and were thought to be the heme sensor, which controls the expression of the heme oxgenase gene (hmu0). This research aims to depict the paradigm of heme sensor proteins which have never been characterized.
The ChrS protein which was overproduced in E. coli cytoplasmic membranes exhibited autophophorylation activity in the presence of Mg. The kinase activity was significantly stimulated by heme. In contrast, porphyrin and other metalloporphyrins gave no effect. This indicates that ChrS is a heme-specific sensor kinase.
ChrS was shown to contain six transmembrane segments by means of phoA and lacZ fusion experiments. Site-directed mutagenesis revealed that His21 in transmembrane segment I plays a crucial role for heme-dependent kinase regulation.
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Research Products
(6 results)
