This family is approximately 130 residues. Dali search indicates this protein carries a NTF2-fold with a hydrophobic cavity as a structural homologue to 1JB2, 2R4I, 3FSD and 2UX0. In this hydrophobic cavity, Arg 118 provides the H-bonding force to hold a PEG molecule from crystallisation. The interface interaction suggests that the biomolecule of Swiss:Q46KI2 is a dimer. Two members of the family are annotated as putative EF-Tu domain 2 but there is no match to this family so this is likely to be a false assignment. There are two highly conserved tryptophan residues towards the C-terminal end of the family.