This is a family of conserved hypothetical proteins found in both prokaryotes and eukaryotes. While the function of these proteins is not known, the crystal structure of <db_xref db="SWISSPROT" dbkey="P44681"/> from <taxon tax_id="727">Haemophilus influenzae</taxon> has been determined [<cite idref="PUB00016351"/>].This protein consists of three domains: an N-terminal domain which has a mononucleotide binding fold typical for the P-loop NTPases, a central domain which forms an alpha-helical coiled coil, and a C-terminal domain composed of a six-stranded half-barrel curved around an alpha helix. The central and C-terminal domains are topologically similar to RNA-binding proteins, while the N-terminal region contains the features typical of GTP-dependent molecular switches. The purified protein was capable of binding both double-stranded nucleic acid and GTP. It was suggested, therefore, that this protein might be part of a nucleoprotein complex and could function as a GTP-dependent translation factor.