RNA 5' triphosphatase

First step of cellular mRNA capping, in which the 5'-triphosphate RNA is converted into 5'-diphosphate RNA. .

Enzymatic reaction:

RNA triphosphatase: Rhea 67004

There are at least 4 triphosphatases families that have different fold: .

Tunnel metalloenzyme (TTM) family

These dimeric enzymes are characterized by a tunnel architecture consisting of 8 antiparallel beta sheets.

Mechanism:The active site consists of more than 15 sites that bind a metal ion and gamma phosphate from the mRNA.

virus	RNA TPase
Vaccinia (Poxvirus)	D1R
Mimivirus	MimiCE
Chlorellavirus	A449R
Baculovirus	LEF-4

These triphosphatases function on the model of cysteine phosphatases

virus	RNA TPase Rhea 67004
Hoat metazoan	RNGTT: CysPhos-TPase
Baculovirus	PTP/BVP: CysPhos-TPase
Iridovirus	ORF064L: CysPhos-TPase

(Histidine-triad like (HIT-like) family)

(Flavi-like family)