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Literature summary for 2.7.7.6 extracted from

  • Imburgio, D.; Anikin, M.; McAllister, W.T.
    Effects of substitutions in a conserved DX2GR sequence motif, found in many DNA-dependent nucleotide polymerases, on transcription by T7 RNA polymerase (2002), J. Mol. Biol., 319, 37-51.
    View publication on PubMed
Search for more literature for 2.7.7.6

Protein Variants

Protein Variants Comment Organism
D421A mutation results in an enzyme with reduced activity and altered patterns of transcription Escherichia phage T7
D421T mutation results in an enzyme with reduced activity and altered patterns of transcription Escherichia phage T7
E813A/D814A significantly decreased elongation rate, the mutation changes the effect of diphosphate on the 3'-5'-exonuclease reaction, whose addition stimulates the production of UMP through hydrolysis rather than of UTP through diphosphorolysis. The mutation makes the 3'-exonuclease activity independent of TTP. The mutation changes the response of TEC to diphosphate: instead of causing diphosphorolysis it stimulates the exonuclease reaction Escherichia coli
N458A significantly decreased elongation rate Escherichia coli
R1106A significantly decreased elongation rate, enhanced exonuclease activity Escherichia coli
R423A mutation results in an enzyme with reduced activity and altered patterns of transcription Escherichia phage T7
R423K mutation results in an enzyme with reduced activity and altered patterns of transcription Escherichia phage T7
R425K mutation results in an enzyme with reduced activity and altered patterns of transcription Escherichia phage T7
W422A mutation results in an enzyme that has nearly normal levels of activity and exhibits patterns of transcription that are similar to that of the wild-type enzyme Escherichia phage T7
W422F mutation results in an enzyme that has nearly normal levels of activity and exhibits patterns of transcription that are similar to that of the wild-type enzyme Escherichia phage T7
W422R mutation results in an enzyme that has nearly normal levels of activity and exhibits patterns of transcription that are similar to that of the wild-type enzyme Escherichia phage T7
W422S mutation results in an enzyme that has nearly normal levels of activity and exhibitspatterns of transcription that arew similar to that of the wild-type enzyme Escherichia phage T7

KM Value [mM]

KM Value [mM] KM Value Maximum [mM] Substrate Comment Organism Structure
0.0095
-
 ATP pH 7.9, 37°C, wild-type enzyme Escherichia phage T7
0.016
-
 ATP pH 7.9, 37°C, mutant enzyme W422A Escherichia phage T7
0.036
-
 ATP pH 7.9, 37°C, mutant enzyme Y427A Escherichia phage T7
0.067
-
 ATP pH 7.9, 37°C, mutant enzyme D421A Escherichia phage T7
0.137
-
 ATP pH 7.9, 37°C, mutant enzyme R423A Escherichia phage T7
0.282
-
 ATP pH 7.9, 37°C, mutant enzyme R425K Escherichia phage T7
0.384
-
 ATP pH 7.9, 37°C, mutant enzyme R425A Escherichia phage T7

Metals/Ions

Metals/Ions Comment Organism Structure
Mg2+ the active center of the enzyme involves a symmetrical pair of Mg2+ ions that switch roles in synthesis and degradation. One ion is retained permanently and the other is recruited ad hoc for each act of catalysis. The weakly bound Mg2+ is stabilized in the active center in different modes depending on the type of reaction: during synthesis by the beta,gamma-phosphates of the incoming substrate and during hydrolysis by the phosphates of a non-base-paired nucleoside triphosphate Escherichia coli

Organism

Organism UniProt Comment Textmining
Escherichia coli
-
-
-
Escherichia phage T7
-
-
-

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
ATP + RNAn
-
 Escherichia phage T7 diphosphate + RNAn+1
-
 ?
nucleoside triphosphate + RNAn the enzyme requires DNA as template Escherichia coli diphosphate + RNAn+1
-
 ?
nucleoside triphosphate + RNAn the enzyme requires DNA as template Escherichia phage T7 diphosphate + RNAn+1
-
 ?

Turnover Number [1/s]

Turnover Number Minimum [1/s] Turnover Number Maximum [1/s] Substrate Comment Organism Structure
0.00065
-
 ATP pH 7.9, 37°C, mutant enzyme R425A Escherichia phage T7
0.0013
-
 ATP pH 7.9, 37°C, mutant enzyme R423A Escherichia phage T7
0.005
-
 ATP pH 7.9, 37°C, mutant enzyme D421A Escherichia phage T7
0.0135
-
 ATP pH 7.9, 37°C, mutant enzyme R425K Escherichia phage T7
0.253
-
 ATP pH 7.9, 37°C, mutant enzyme Y427A Escherichia phage T7
0.35
-
 ATP pH 7.9, 37°C, mutant enzyme W422A Escherichia phage T7
0.482
-
 ATP pH 7.9, 37°C, wild-type enzyme Escherichia phage T7