6XP8

The crystal structure of TfuA involved in peptide backbone thioamidation from Methanosarcina acetivorans

Summary for 6XP8

• Entry DOI: 10.2210/pdb6xp8/pdb
• Descriptor: TfuA domain-containing protein (2 entities in total)
• Functional Keywords: ycao, tfua, thioamidation, biosynthetic protein
• Biological source: Methanosarcina acetivorans
• Total number of polymer chains: 1
• Total formula weight: 23887.32

Authors

Dong, S.-H.,Nair, S.K. (deposition date: 2020-07-08, release date: 2021-03-17, Last modification date: 2024-03-06)

Primary citation

Liu, A.,Si, Y.,Dong, S.H.,Mahanta, N.,Penkala, H.N.,Nair, S.K.,Mitchell, D.A.
Functional elucidation of TfuA in peptide backbone thioamidation.
Nat.Chem.Biol., 17:585-592, 2021

PubMed Abstract: YcaO enzymes catalyze several post-translational modifications on peptide substrates, including thioamidation, which substitutes an amide oxygen with sulfur. Most predicted thioamide-forming YcaO enzymes are encoded adjacent to TfuA, which when present, is required for thioamidation. While activation of the peptide amide backbone is well established for YcaO enzymes, the function of TfuA has remained enigmatic. Here we characterize the TfuA protein involved in methyl-coenzyme M reductase thioamidation and demonstrate that TfuA catalyzes the hydrolysis of thiocarboxylated ThiS (ThiS-COSH), a proteinaceous sulfur donor, and enhances the affinity of YcaO toward the thioamidation substrate. We also report a crystal structure of a TfuA, which displays a new protein fold. Our structural and mutational analyses of TfuA have uncovered conserved binding interfaces with YcaO and ThiS in addition to revealing a hydrolase-like active site featuring a Ser-Lys catalytic pair.

PubMed: 33707784
DOI: 10.1038/s41589-021-00771-0

Experimental method

X-RAY DIFFRACTION (1.65 Å)