This family contains OB-fold domains that bind to nucleic acids. The family includes the anti-codon binding domain of lysyl, aspartyl, and asparaginyl -tRNA synthetases (see pfam00152). Aminoacyl-tRNA synthetases catalyze the addition of an amino acid to the appropriate tRNA molecule EC:6.1.1.-. This family also includes part of RecG helicase involved in DNA repair. Replication factor A is a hetero-trimeric complex, that contains a subunit in this family. This domain is also found at the C-terminus of bacterial DNA polymerase III alpha chain.