Cloning, Purification, and Crystallization of a Bacterial Gene Expression Regulator--Hfq Protein from Escherichia coli

I. M. Vassilieva^1*, M. V. Rouzanov¹, N. V. Zelinskaya¹, I. Moll², U. Bläsi², and M. B. Garber¹

¹Institute of Protein Research, Russian Academy of Sciences, Pushchino, Moscow Region, 142290 Russia; fax: (095) 924-0493; E-mail: yuvas@vega.protres.ru

²Institute of Microbiology and Genetics, Vienna Biocenter, Dr. Bohrgasse 9, 1030 Vienna, Austria; fax: +43-1-4277-9546; E-mail: UDO@gem.univie.ac.at

^* To whom correspondence should be addressed.

Received October 3, 2001; Revision received November 27, 2001

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Thermostable RNA-binding protein Hfq (also denoted HF1) is a multifunctional expression regulator of many bacterial genes. The regulation takes place both at a translation level (directly) and transcription level (indirectly through the stimulation of bacterial RNA polymerase sigma^S-subunit translation). We have cloned and overexpressed the hfq gene from E. coli and developed a purification procedure for the protein. Using gel filtration and ultracentrifugation techniques it was shown that the obtained Hfq protein is highly homogeneous and well dissolved. It has been crystallized and can be used for structural investigations.

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KEY WORDS: Hfq, HF1, RNA-binding protein, regulation of bacterial gene expression, Escherichia coli

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