3sb2

Publication Abstract from PubMed

The RNA chaperone Hfq is a homohexamer protein identified as an E. coli host factor involved in phage Qbeta replication and it is an important posttranscriptional regulator of several types of RNA, affecting a plethora of bacterial functions. Although twenty Hfq crystal structures have already been reported in the Protein Data Bank (PDB), new insights into these protein structures can still be discussed. In this work, the structure of Hfq from the beta-proteobacterium Herbaspirillum seropedicae, a diazotroph associated with economically important agricultural crops, was determined by X-ray crystallography and small-angle X-ray scattering (SAXS). Biochemical assays such as exclusion chromatography and RNA-binding by the electrophoretic shift assay (EMSA) confirmed that the purified protein is homogeneous and active. The crystal structure revealed a conserved Sm topology, composed of one N-terminal alpha-helix followed by five twisted beta-strands, and a novel pi-pi stacking intra-subunit interaction of two histidine residues, absent in other Hfq proteins. Moreover, the calculated ab initio envelope based on small-angle X-ray scattering (SAXS) data agreed with the Hfq crystal structure, suggesting that the protein has the same folding structure in solution.

Structural characterization of the RNA chaperone Hfq from the nitrogen-fixing bacterium Herbaspirillum seropedicae SmR1.,Kadowaki MA, Iulek J, Barbosa JA, Pedrosa FD, de Souza EM, Chubatsu LS, Monteiro RA, de Oliveira MA, Steffens MB Biochim Biophys Acta. 2011 Dec 2;1824(2):359-365. PMID:22154803^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.