Difference between revisions of "Phosphatase Subfamily RNGTT"
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=== Evolution === | === Evolution === | ||
| − | RNGTT is ubiquitous in holozoan and usually there is a single copy in each organism. As described in below, RNGTT has two distinct enzymatic domains: RNA triphosphatase and guanylyltransferase (GTase). In fungi, the two enzymatic activities are contained in separate but necessarily interacting proteins <cite>Ho99</cite>. The GTase is conserved across eukaryotes | + | RNGTT is ubiquitous in holozoan and usually there is a single copy in each organism. As described in below, RNGTT has two distinct enzymatic domains: RNA triphosphatase and guanylyltransferase (GTase). In fungi, the two enzymatic activities are contained in separate but necessarily interacting proteins <cite>Ho99</cite>. The GTase is conserved across eukaryotes; The phosphatase is found across eukaryotes including plants except fungi. Fungi have unique RNA triphosphatase distinct from that of RNGTT in other clades in sequence and structure <cite>Lima99, Chu11</cite>. Thus, RNGTT emerged in early eukaryotes but lost in fungi perhaps through gene fission. |
=== Domain === | === Domain === | ||
Revision as of 18:14, 27 February 2015
Phosphatase Classification: Fold CC1: Superfamily CC1: Family DSP: Subfamily RNGTT
RNGTT is an mRNA capping enzyme found in holozoan.
Evolution
RNGTT is ubiquitous in holozoan and usually there is a single copy in each organism. As described in below, RNGTT has two distinct enzymatic domains: RNA triphosphatase and guanylyltransferase (GTase). In fungi, the two enzymatic activities are contained in separate but necessarily interacting proteins [1]. The GTase is conserved across eukaryotes; The phosphatase is found across eukaryotes including plants except fungi. Fungi have unique RNA triphosphatase distinct from that of RNGTT in other clades in sequence and structure [2, 3]. Thus, RNGTT emerged in early eukaryotes but lost in fungi perhaps through gene fission.
Domain
Holozoan RNGTT has three conserved regions: N-terminal phosphatase domain removing the gamma phosphate, guanylyltransferase (GTase) domain adding GMP, and C-terminal conserved region.
Function
RNGTT is an mRNA capping enzyme. Capping of nascent RNA 5′ ends is accomplished in eukaryotic cells and for most viruses in three sequential catalytic steps: removal of the gamma phosphate by RNA triphosphatase (RTase), addition of GMP from GTP by guanylyltransferase (GTase) via a phosphoamide linked GMP–enzyme intermediate, and N7 methylation of the added GMP by RNA (guanine-N7) methyltransferase (MTase) [3]. RNGTT carries out the first two steps through its phosphatase domain (RTase) and GTase domain.
References
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