nucleotide-binding domain (NBD) of O-sialoglycoprotein endopeptidase (OSGEP) and similar proteins mainly from eukaryotes
OSGEP (EC 2.3.1.234), also called tRNA N6-adenosine threonylcarbamoyltransferase, N6-L-threonylcarbamoyladenine synthase, t(6)A synthase, t(6)A37 threonylcarbamoyladenosine biosynthesis protein OSGEP, tRNA threonylcarbamoyladenosine biosynthesis protein OSGEP, is a component of the EKC/KEOPS complex that 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. The complex is probably involved in the transfer of the threonylcarbamoyl moiety of threonylcarbamoyl-AMP (TC-AMP) to the N6 group of A37. OSGEP likely plays a direct catalytic role in this reaction but requires other protein(s) of the complex to fulfill this activity. OSGEP is the mammalian orthologue of kinase-associated endopeptidase Kae1.