- Hfq protein
The Hfq protein was discovered in 1968 as an "
E. coli " host factor that was essential for replication of thebacteriophage Qβ.cite journal | author = August JT, Eoyang L, De Fernandez MT, "et al" | title = Phage-specific and host proteins in the replication of bacteriophage RNA | journal = Fed. Proc. | volume = 29 | issue = 3 | pages = 1170–5 | year = 1970 | pmid = 4315363 | doi = | issn = ] It is found to be involved in a variety of RNA modification processes. It has been shown that Hfq targets mRNA transcripts for degradation. The protein is related to the Sm proteins found in thespliceosome . Six copies of the Hfq protein form a hexagonal ring.cite journal | author = Sauter C, Basquin J, Suck D | title = Sm-like proteins in Eubacteria: the crystal structure of the Hfq protein from Escherichia coli | journal = Nucleic Acids Res. | volume = 31 | issue = 14 | pages = 4091–8 | year = 2003 | pmid = 12853626 | doi = | issn = ] A number of small bacterial RNAs have been shown to bind to Hfq:cite journal | author = Zhang A, Wassarman KM, Rosenow C, Tjaden BC, Storz G, Gottesman S | title = Global analysis of small RNA and mRNA targets of Hfq | journal = Mol. Microbiol. | volume = 50 | issue = 4 | pages = 1111–24 | year = 2003 | pmid = 14622403 | doi = | issn = ]Most of these RNAs share a similar structure composed of three
stem-loop s.Crystallographic structures
Six crystallographic structures of 4 different Hfq proteins have been published so far; "
E. coli " Hfq (PDB|1HK9), "P. aeruginosa " Hfq in a low salt condition (PDB2|1U1S) and a high salt condition (PDB2|1U1T), Hfq from "S. aureus " with bound RNA (PDB2|1KQ2) and without (PDB2|1KQ1), and the Hfq(-like) protein from "M. jannaschii " (PDB2|2QTX).All six structures confirm the hexameric ring-shape of a Hfq protein complex.
References
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