(a) Schematic representation of the difference in the activation of L-Aspartic acid by aspartyl-tRNA synthetase (AspRS) and Asparagine synthetase A (AsnA). (b) Lysyl tRNA synthetase rooted sequence based phylogeny of Asparagine synthetase A with aspartyl and asparagine tRNA synthetases. This tree is constructed using MEGA v5.0 using maximum likelihood method based on JTT matrix model. (c) Structure dependent sequence based phylogeny of the crystal structures of AsnA from E. coli (EcAsnA: 11AS); P. abyssi (PaAsnA: 3P8Y), AspRS from T. kodakarensis (TkAspRS: 3NEM); T. thermophilus (TtAspRS: 1EFW); T. thermophilus (TtAspRS2: 1IL2); S. cerevisiae (ScAspRSf: 1E0V) and AsnRS from E. histolytica (EhAsnRS: 3M4P); B. malayi (BmAsnRS: 2XGT). The tree is constructed using the structure based sequence alignment generated using MUSTANG structural alignment program. (d) A snapshot of the active site residues in EcASA (PDB: 11AS A chain; Red color) with LmASA structural model (blue color). Structural comparison shows the superposition of the flipping loop and active site residues from both the structures. The pairwise sequence alignment of the corresponding structural superposition with the respective color coding is also shown. The ATP binding Glycine residues are shown in BOLD, underlined fonts. The residues in the flipping loop are shown in the yellow boxes and the active site residues are shown in BOLD font.
Gowri et al. BMC Genomics 2012 13:621 doi:10.1186/1471-2164-13-621