Staphylococcus aureus thiaminase II: oligomerization warrants proteolytic protection against serine proteases.
Staphylococcus aureus TenA (SaTenA) is a thiaminase type II enzyme that catalyzes the deamination of aminopyrimidine, as well as the cleavage of thiamine into 4-amino-5-hydroxymethyl-2-methylpyrimidine (HMP) and 5-(2-hydroxyethyl)-4-methylthiazole (THZ), within thiamine (vitamin B1) metabolism. Further, by analogy with studies of Bacillus subtilis TenA, SaTenA may act as a regulator controlling the secretion of extracellular proteases such as the subtilisin type of enzymes in bacteria. Thiamine biosynthesis has been identified as a potential drug target of the multi-resistant pathogen S. aureus and therefore all enzymes involved in the S. aureus thiamine pathway are presently being investigated in detail. Here, the structure of SaTenA, determined by molecular replacement and refined at 2.7 Å resolution to an R factor of 21.6% with one homotetramer in the asymmetric unit in the orthorhombic space group P212121, is presented. The tetrameric state of wild-type (WT) SaTenA was postulated to be the functional biological unit and was confirmed by small-angle X-ray scattering (SAXS) experiments in solution. To obtain insights into structural and functional features of the oligomeric SaTenA, comparative kinetic investigations as well as experiments analyzing the structural stability of the WT SaTenA tetramer versus a monomeric SaTenA mutant were performed.
['Begum|Afshan|A|', 'Drebes|Julia|J|', 'Kikhney|Alexey|A|', 'Müller|Ingrid B|IB|', 'Perbandt|Markus|M|', 'Svergun|Dmitri|D|', 'Wrenger|Carsten|C|', 'Betzel|Christian|C|']
D006801:Humans D006867:Hydrolases D008958:Models, Molecular D016297:Mutagenesis, Site-Directed D011487:Protein Conformation D055503:Protein Multimerization D059748:Proteolysis D057057:Serine Proteases D013203:Staphylococcal Infections D013211:Staphylococcus aureus D020860:Subtilisin D013831:Thiamine D014357:Trypsin
thiaminases thiamine vitamin B1 proteolytic stability transcriptional activators