Assessment of function annotation transfer between the DUF925 family and the Nucleotidyl transferase family (d.218.1.4). a) The structural alignment between two proteins in the SCOP superfamily of Nucleotidyltransferase, 1miv (shown in blue) and 7icq (shown in green). The active site residues in 1miv are shown in red, and the active site residues of 7icq are shown in blue, both in the stick format. The nucleotide binding residues in 1miv (Asp40 and Asp42) are seen to be aligned with the nucleotide binding residues of 7icq (Asp190 and Asp192). The active site is mostly conserved, but there are some differences between the two proteins which could perhaps explain the different substrates and mechanism employed by the two proteins. b) The alignment between the DUF925 family proteins and the SCOP family d.218.1.4 proteins. The alignment shows that the Aspartate residues important for binding nucleotides are conserved across the two families, but the conservation of other active site residues is not observed. Alignment figure generated using Jalview  and structure figure generated using PyMOL .