InterPro domain: IPR014560

There is currently no experimental data for members of this group. However, the proteins are distantly related to the archaeal DNA/RNA-binding protein Alba, also called histone-like protein ( IPR013795 ), and its eukaryotic homologues RNase P/MRP subunits Pop7/Rpp20 ( IPR014612 ) and Rpp25. Therefore, members of this group can be predicted to be involved in RNA and/or DNA binding.

Structural comparisons have shown that Alba (Sso10b2 from the thermoacidophilic archaeon Sulfolobus solfataricus) is topologically similar to several RNA-binding proteins (or A-DNA-binding) and includes IF3-C, YhhP, and DNase I. All of them have a similar IF3-C fold [ 1 , 2 ] and it has been suggested that the ancestral function of the IF3-C fold is related to RNA interaction, and that the Alba superfamily proteins originated as RNA-binding proteins that formed various ribonucleoprotein complexes, probably including RNase P, and were then recruited as a chromosomal protein within the crenarchaeal lineage [ 3 ]. Based on this, it has been suggested that the archaeal Alba proteins ( PIRSF028732 ) are involved in RNA binding as well as DNA binding [ 3 , 3 ], a prediction that has been confirmed experimentally [ 3 ].

For more information about Alba, please see PIRSF028732 .

1. Crystal structure of the hyperthermophilic archaeal DNA-binding protein Sso10b2 at a resolution of 1.85 Angstroms. J. Bacteriol. 185, 4066-73
2. The two faces of Alba: the evolutionary connection between proteins participating in chromatin structure and RNA metabolism. Genome Biol. 4, R64
3. Ssh10b, a conserved thermophilic archaeal protein, binds RNA in vivo. Mol. Microbiol. 50, 1605-15