pfam07973: tRNA_SAD (This model is not part of the current CDD release)
Threonyl and Alanyl tRNA synthetase second additional domain
The catalytically active from of threonyl/alanyl tRNA synthetase is a dimer. Within the tRNA synthetase class II dimer, the bound tRNA interacts with both monomers making specific interactions with the catalytic domain, the C-terminal domain, and this domain (the second additional domain). The second additional domain is comprised of a pair of perpendicularly orientated antiparallel beta sheets, of four and three strands, respectively, that surround a central alpha helix that forms the core of the domain.
Jiyao W et al.(2023). "The conserved domain database in 2023.",