{PDOC51061} {PS51061; R3H} {BEGIN} ********************** * R3H domain profile * ********************** The R3H domain is a conserved sequence motif found in proteins from a diverse range of organisms including eubacteria, green plants, fungi and various groups of metazoans, but not in archaea and Escherichia coli. The R3H domain contains an invariant arginine and a highly conserved histidine, that are separated by three residues. It also displays a conserved pattern of hydrophobic residues, prolines and glycines. It can be found alone, in association with AAA domain (see ) or with various DNA/RNA binding domains like DSRM, KH, G-patch (see ), PHD (see ), DEAD box (see ), or RRM (see ). The functions of these domains indicate that the R3H domain might be involved in polynucleotide- binding, including DNA, RNA and single-stranded DNA [1]. The 3D structure of the R3H domain has been solved (see ). The fold presents a small motif, consisting of a three-stranded antiparallel beta- sheet, against which two alpha-helices pack from one side. This fold is related to the structures of the YhhP protein and the C-terminal domain of the translational initiation factor IF3. Three conserved basic residues cluster on the same face of the R3H domain and could play a role in nucleic acid recognition. An extended hydrophobic area at a different site of the molecular surface could act as a protein-binding site [2]. Proteins currently known to contain an R3H domain are: - Mammalian SMB2-related proteins, which are involved in DNA-binding, and are specific to a 5'-phosphorylated single-stranded guanine-rich sequence related to the immunoglobulin mu chain switch region. - Bacterial JAG proteins. - Mammalian R3H domain protein 1. The profile developed covers the entire R3H structure. -Sequences known to belong to this class detected by the profile: ALL. -Other sequence(s) detected in Swiss-Prot: NONE. -Last update: January 2005 / First entry. [ 1] Grishin N.V. "The R3H motif: a domain that binds single-stranded nucleic acids." Trends Biochem. Sci. 23:329-330(1998). PubMed=9787637 [ 2] Liepinsh E., Leonchiks A., Sharipo A., Guignard L., Otting G. "Solution structure of the R3H domain from human Smubp-2." J. Mol. Biol. 326:217-223(2003). PubMed=12547203 -------------------------------------------------------------------------------- PROSITE is copyrighted by the SIB Swiss Institute of Bioinformatics and distributed under the Creative Commons Attribution-NonCommercial-NoDerivatives (CC BY-NC-ND 4.0) License, see https://prosite.expasy.org/prosite_license.html -------------------------------------------------------------------------------- {END}