TenA_C proteins similar to Helicobacter pylori TenA (HP1287
This family of TenA proteins belongs to the TenA_C class as it has a conserved active site Cys residue; the double Glu residues identified in the active site of TenA_E from the archaeon Pyrococcus furiosus is conserved in this family. TenA_C proteins (EC 3.5.99.2) catalyze the hydrolysis of the thiamin breakdown product 4-amino-5-amino-methyl-2-methylpyrimidine (amino-HMP) to 4-amino-5-hydroxymethyl-2-methylpyrimidine (HMP) in a thiamin salvage pathway. This family includes Helicobacter pylori TenA (HP1287) protein which is thought to catalyze a salvage reaction in thiamin metabolism, however its pyrimidine substrate has not yet been identified. It has also been suggested that TenA proteins act as transcriptional regulators based on changes in gene-expression patterns when TenA is overexpressed in Bacillus subtilis, however this effect may be indirect. HP1287 may contribute to stomach colonization and persistence.
Feature 1: conserved active site residues [active site], 3 residue positions
Conserved feature residue pattern:E C E
Evidence:
Comment:these proteins have a conserved active site Cys residue, and 2 conserved Glu residues in the active site; the Cys is thought to act as a nucleophile in the thiaminase reaction, Glu are thought to interact with the substituent at the 5-position of the pyrimidine ring
Jiyao W et al.(2023). "The conserved domain database in 2023.",