Protein
tRNA threonylcarbamoyladenosine biosynthesis protein TsaB
Organism
Escherichia coli (strain K12)
Function
Required for the formation of a threonylcarbamoyl group on adenosine at position 37 (t(6)A37) in tRNAs that read codons beginning with adenine. Is probably involved in the transfer of the threonylcarbamoyl moiety of threonylcarbamoyl-AMP (TC-AMP) to the N6 group of A37, together with TsaD and TsaE. TsaB seems to play an indirect role in the t(6)A biosynthesis pathway, possibly in regulating the core enzymatic function of TsaD. In fact, can act as a protease that specifically degrades TsaD in vitro; therefore TsaB may post-translationally regulate cellular pools of TsaD via proteolytic degradation. Does not show sialoglycoprotease activity against glycophorin A.
Similarity
Belongs to the KAE1 / TsaD family. TsaB subfamily.
Sequence
MRILAIDTATEACSVALWNDGTVNAHFELCPREHTQRILPMVQDILTTSGTSLTDINALAYGRGPGSFTGVRIGIGIAQGLALGAELPMIGVSTLMTMAQGAWRKNGATRVLAAIDARMGEVYWAEYQRDENGIWHGEETEAVLKPEIVHERMQQLSGEWVTVGTGWQAWPDLGKESGLVLRDGEVLLPAAEDMLPIACQMFAEGKTVAVEHAEPVYLRNNVAWKKLPGKE