TenA_E proteins similar to Streptococcus pneumoniae Spr0628 and Saccharomyces cerevisiae S288C PET18
This family of TenA proteins belongs to the TenA_E class, and lacks the conserved active site Cys residue of the TenA_C class; most have a pair of structurally conserved Glu residues in the active site. TenA_C proteins (EC 3.5.99.2; aminopyrimidine aminohydrolase, also known as thiaminase II) 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; the role of TenA_E proteins is less clear. Arabidopsis thaliana TenA_E (not belonging to this family) hydrolyzes amino-HMP to AMP, and the N-formyl derivative of amino-HMP to amino-HMP. Members of this family include the putative thiaminase Streptococcus pneumoniae Spr0628, and Saccharomyces cerevisiae S288C PET18, a protein of unknown function whose expression is induced in the absence of thiamin. 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. Many proteins in this family have yet to be characterized.
Feature 1: conserved active site residues [active site], 2 residue positions
Conserved feature residue pattern:E E
Evidence:
Comment:these proteins lack a conserved active site Cys residue, and have 2 conserved Glu residues in the active site; these Glu residues 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.",