Staphylococcus aureus thiaminase II: oligomerization warrants proteolytic protection against serine proteases

The crystal structure of TenA from methicillin-resistant S. aureus, which is a thiaminase type II in the thiamine metabolism of the pathogen and may act as a transcriptional activator controlling the secretion of extracellular proteases, is reported. Mutagenic studies reveal the stabilizing effect of the tetrameric assembly against proteolytic digestion.