Protein Hfq

Function

Protein Hfq (Hfq) (Host Factor for Qβ) or RNA-binding protein Hfq is stimulating base-pairing between sRNA and target mRNA by binding both RNAs via three RNA-binding surfaces. Hfq is found in enteric bacteria^[1]. Hfq binds RNA via poly(A-R-N) triplets where A is adenosine, R is purine nucleotide and N is any nucleotide^[2].

Relevance

Since Hfq is required for gene regulation and infectivity of some Gram-negative bacteria its mutations can eliminate infectivity of Lyme disease caused by the bacteria Borellia burgdorferi, for example^[3].

Structural highlights

The biological assembly of Protein Hfq from E. coli is (PDB code 4ht9). The 3D structure of the complex between Hfq and shows the poly(A) binding at the distal face of Hfq and poly(U) binding at its proximal face. For the poly(A) A-R-N binding site the A site shows . The . The N site does not show any interaction. The poly(U) binding site of Hfq is a classical uridine binding pocket with both stacking and hydrogen bonding interactions^[4].