Crystal structure of the 'PhoU-like' phosphateuptake regulatorfrom Aquifex aeolicus
The phoU gene of Aquifex aeolicus encodes a protein called PHOU{_}AQUAE with sequence similarity to the PhoU protein of Escherichia coli. Despite the fact that there is a large number of family members (more than 300) attributed to almost all known bacteria and despite PHOU{_}AQUAE's association with the regulation of genes for phosphate metabolism, the nature of its regulatory function is not well understood. Nearly one-half of these PhoU-like proteins, including both PHOU{_}AQUAE and the one from E. coli, form a subfamily with an apparent dimer structure of two PhoU domains on the basis of their amino acid sequence. The crystal structure of PHOU{_}AQUAE (a 221-amino-acid protein) reveals two similar coiled-coil PhoU domains, each forming a three-helix bundle. The structures of PHOU{_}AQUAE proteins from both a soluble fraction and refolded inclusion bodies (at resolutions of 2.8 and 3.2 Angstroms, respectively) showed no significant differences. The folds of the PhoU domain and Bag domains (for a class of cofactors of the eukaryotic chaperone Hsp70 family) are similar. Accordingly, we propose that gene regulation by PhoU may occur by association of PHOU{_}AQUAE with the ATPase domain of the histidine kinase PhoR, promoting release of its substrate PhoB. Other proteins that share the PhoU domain fold include the coiled-coil domains of the STAT protein, the ribosome-recycling factor, and structural proteins like spectrin.
- Research Organization:
- Ernest Orlando Lawrence Berkeley NationalLaboratory, Berkeley, CA (US)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC02-05CH11231
- OSTI ID:
- 925410
- Report Number(s):
- LBNL--57455; BnR: 400412000
- Journal Information:
- Journal of Bacteriology, Journal Name: Journal of Bacteriology Journal Issue: 12 Vol. 187; ISSN JOBAAY; ISSN 0021-9193
- Country of Publication:
- United States
- Language:
- English
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