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Literature summary for 3.6.1.74 extracted from

  • Tsukamoto, T.; Shibagaki, Y.; Murakoshi, T.; Suzuki, M.; Nakamura, A.; Gotoh, H.; Mizumoto, K.
    Cloning and characterization of two human cDNAs encoding the mRNA capping enzyme (1998), Biochem. Biophys. Res. Commun., 243, 101-108 .
    View publication on PubMed
Search for more literature for 3.6.1.74

Cloned(Commentary)

Cloned (Comment) Organism
gene hCAP1a, DNA and amino acid sequence determination and analysis, sequence comparisons, recombinant expression of His-tagged wild-type and mutant enzymes in Escherichia coli strain BL21(DE3)pLysS, RT-PCR expression analysis Homo sapiens
gene hCAP1b, DNA and amino acid sequence determination and analysis, sequence comparisons, recombinant expression of His-tagged enzyme in Escherichia coli strain BL21(DE3)pLysS, RT-PCR expression analysis Homo sapiens

Protein Variants

Protein Variants Comment Organism
additional information construction of C-terminal deletion and of N-terminal mutants (His-CAP1a (1-213) and His-CAP1a (229-597)) of hCAP1a Homo sapiens

Natural Substrates/ Products (Substrates)

Natural Substrates Organism Comment (Nat. Sub.) Natural Products Comment (Nat. Pro.) Rev. Reac.
a 5'-triphospho-[mRNA] + H2O Homo sapiens
-
 a 5'-diphospho-[mRNA] + phosphate
-
 ?

Organism

Organism UniProt Comment Textmining
Homo sapiens
-
-
-
Homo sapiens O60942
-
-

Purification (Commentary)

Purification (Comment) Organism
recombinant His-tagged enzyme from Escherichia coli strain BL21(DE3)pLysS by nickel affinity chromatography Homo sapiens
recombinant His-tagged wild-type and mutant enzymes from Escherichia coli strain BL21(DE3)pLysS by nickel affinity chromatography Homo sapiens

Source Tissue

Source Tissue Comment Organism Textmining
cerebellum
-
 Homo sapiens
-
heart
-
 Homo sapiens
-
HeLa cell
-
 Homo sapiens
-
kidney
-
 Homo sapiens
-
large intestine
-
 Homo sapiens
-
liver
-
 Homo sapiens
-
lung
-
 Homo sapiens
-
additional information hCAP1a mRNAs is detected in all tissues tested, RT-PCR expression analysis Homo sapiens
-
additional information hCAP1b mRNAs is detected in all tissues tested, but to a lesser extent than hCAP1a, RT-PCR expression analysis Homo sapiens
-
muscle
-
 Homo sapiens
-
skin
-
 Homo sapiens
-
spleen
-
 Homo sapiens
-
telencephalon
-
 Homo sapiens
-
testis
-
 Homo sapiens
-
thyroid gland
-
 Homo sapiens
-

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
a 5'-triphospho-[mRNA] + H2O
-
 Homo sapiens a 5'-diphospho-[mRNA] + phosphate
-
 ?
additional information the purified recombinant hCAP1a gene product, hCAP1a, exhibits both mRNA 5'-triphosphatase and mRNA guanylyltransferase activities. The N-terminal 213 amino acid fragment containing a tyrosine-specific protein phosphatase motif catalyzes the RNA 5'-triphosphatase activity, and the C-terminal 369 amino acid fragment exhibits the mRNA guanylyltransferase activity. The recombinant protein hCAP1a releases [32P]Pi from [gamma-32P]triphosphate-terminated to RNA, but it is less active with [gamma-32P]GTP, indicating that it recognize the RNA chain Homo sapiens ?
-
-
additional information the purified recombinant hCAP1b gene product, hCAP1b, shows RNA 5'-triphosphatase activity, but neither enzyme-GMP covalent complex formation nor cap structure formation is detected. The recombinant protein hCAP1b releases [32P]Pi from [gamma-32P]triphosphate-terminated to RNA, but it is less active with [gamma-32P]GTP, indicating that it recognize the RNA chain Homo sapiens ?
-
-

Subunits

Subunits Comment Organism
? x * 64000, recombinant His-tagged wild-type enzyme hCAP1b, SDS-PAGE Homo sapiens
? x * 70000, recombinant His-tagged wild-type enzyme hCAP1a, SDS-PAGE Homo sapiens

Synonyms

Synonyms Comment Organism
hCAP1a
-
 Homo sapiens
hCAP1b
-
 Homo sapiens
mRNA capping enzyme
-
 Homo sapiens
mRNA-capping enzyme UniProt Homo sapiens
RNGTT
-
 Homo sapiens

General Information

General Information Comment Organism
evolution the nucleotide sequences of hCAP1a and hCAP1b are identical from the 5' flanking region to codon 503, but are entirely different thereafter. The N-terminal portion of the predicted amino acid sequence contains the motif of the tyrosine specific protein phosphatase active site, [LIVMF]-H-C-x(2)-G-x(3)-[STC]-[STAG]-x-[LIVMFY]. The C-terminal portion of the protein is highly homologous to the known mRNA guanylyltransferases and contains all the motifs, i.e. motifs I, III, IIIa, IV, V, VI, and P, which are commonly observed in viral and cellular mRNA guanylyltransferases except that the motif VI is missing in hCAP1b Homo sapiens
malfunction deletion mutant analysis of hCAP1a shows that the N-terminal 213 amino acid fragment containing a tyrosine-specific protein phosphatase motif catalyzes the RNA 5'-triphosphatase activity, and the C-terminal 369 amino acid fragment exhibits the mRNA guanylyltransferase activity. When RNA 5'-triphosphatase activity is assayed using [gamma-32 P]pppG-RNA, mutant His-hCAP1a(1-213) releases [32P]phosphate, while no [32P]phosphate is released by mutant hCAP1a(229-597). Furthermore, the N-terminal half molecule, hCAP1a(1-213) exhibits no NTPase activity, indicating that this half molecule still retains the specificity for RNA Homo sapiens
additional information the active site for RNA 5'-triphosphatase resides in the N-terminal 213 amino acids fragment, whereas mRNA guanylyltransferase activity resides in the C-terminal 289 amino acid fragment Homo sapiens
physiological function recombinant enzyme hCAP1b shows RNA 5'-triphosphatase activity, but neither enzyme-GMP covalent complex formation nor cap structure formation is detected Homo sapiens
physiological function the mammalian mRNA capping enzyme is a bifunctional enzyme containing RNA 5'-triphosphatase and mRNA guanylyl-transferase activities in a single polypeptide Homo sapiens