InterPro domain: IPR004365

The OB-fold (oligonucleotide/oligosaccharide-binding fold) is found in all three kingdoms and its common architecture presents a binding face that has adapted to bind different ligands. The OB-fold is a five/six-stranded closed beta-barrel formed by 70-80 amino acid residues. The strands are connected by loops of varying length which form the functional appendages of the protein. The majority of OB-fold proteins use the same face for ligand binding or as an active site. Different OB-fold proteins use this 'fold-related binding face' to, variously, bind oligosaccharides, oligonucleotides, proteins, metal ions and catalytic substrates.

This entry contains OB-fold domains that bind to nucleic acids [ 1 ]. It includes the anti-codon binding domain of lysyl, aspartyl, and asparaginyl-tRNA synthetases (See IPR004364 ). Aminoacyl-tRNA synthetases catalyse the addition of an amino acid to the appropriate tRNA molecule 6.1.1 . This domain is found in RecG helicase involved in DNA repair. Replication factor A is a heterotrimeric complex, that contains a subunit in this family [ 2 , 3 ]. This domain is also found at the C terminus of bacterial DNA polymerase III alpha chain.

1. Protein fold recognition using sequence profiles and its application in structural genomics. Adv. Protein Chem. 54, 245-75
2. Rpa4, a homolog of the 34-kilodalton subunit of the replication protein A complex. Mol. Cell. Biol. 15, 3119-28
3. Structure of the single-stranded-DNA-binding domain of replication protein A bound to DNA. Nature 385, 176-81