nucleotide-binding domain (NBD) of TsaD and similar proteins
TsaD (EC 2.3.1.234), also called N6-L-threonylcarbamoyladenine synthase, t(6)A synthase, t(6)A37 threonylcarbamoyladenosine biosynthesis protein TsaD, or tRNA threonylcarbamoyladenosine biosynthesis protein TsaD, is required for the formation of a threonylcarbamoyl group on adenosine at position 37 (t(6)A37) in tRNAs that read codons beginning with adenine. It is involved in the transfer of the threonylcarbamoyl moiety of threonylcarbamoyl-AMP (TC-AMP) to the N6 group of A37, together with TsaE and TsaB. TsaD likely plays a direct catalytic role in this reaction. The family also includes mammalian OSGEP-like protein 1 (OSGEPL1) and yeast protein Qri7, which are the mitochondrial versions of the universal Kae1/TsaD (also known as YgjD) protein and essential for mitochondrial genome maintenance.