Uncharacterized subgroup 1 of the CYTH-like superfamily
Enzymes belonging to the CYTH-like (also known as triphosphate tunnel metalloenzyme (TTM)-like) superfamily hydrolyze triphosphate-containing substrates, require metal cations as cofactors, and have a unique active site located at the center of an eight-stranded antiparallel beta barrel tunnel (the triphosphate tunnel). The name CYTH originated from the gene designation for bacterial class IV adenylyl cyclases (CyaB) and from thiamine triphosphatase. Class IV adenylate cyclases catalyze the conversion of ATP to 3',5'-cyclic AMP (cAMP) and PPi. Thiamine triphosphatase is a soluble cytosolic enzyme which converts thiamine triphosphate to thiamine diphosphate. This domain superfamily also contains RNA triphosphatases, membrane-associated polyphosphate polymerases, tripolyphosphatases, nucleoside triphosphatases, nucleoside tetraphosphatases and other proteins with unknown functions. Proteins of this subgroup are of bacterial origin and have not been characterized.