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Literature summary for 3.1.26.4 extracted from

  • Lai, B.; Li, Y.; Cao, A.; Lai, L.
    Metal ion binding and enzymatic mechanism of Methanococcus jannaschii RNase HII (2003), Biochemistry, 42, 785-791.
    View publication on PubMed
Search for more literature for 3.1.26.4

Cloned(Commentary)

Cloned (Comment) Organism
expression of wild-type and mutants enzymes in Escherichia coli BL21(DE3) Methanocaldococcus jannaschii

Protein Variants

Protein Variants Comment Organism
D112N site-directed mutagenesis, 0.17% activity compared to the wild-type enzyme, no Mn2+ binding Methanocaldococcus jannaschii
D149N site-directed mutagenesis, 0.12% activity and slightly weakened Mn2+ binding properties compared to the wild-type enzyme Methanocaldococcus jannaschii
D7N site-directed mutagenesis, 0.13% activity and slightly weakened Mn2+ binding properties compared to the wild-type enzyme Methanocaldococcus jannaschii
E8Q site-directed mutagenesis, 0.14% activity and slightly weakened Mn2+ binding properties compared to the wild-type enzyme Methanocaldococcus jannaschii

KM Value [mM]

KM Value [mM] KM Value Maximum [mM] Substrate Comment Organism Structure
additional information
-
 additional information Km at 50 mM NaCl not measurable Methanocaldococcus jannaschii
0.012
-
 polyA*dT36 pH 8.0, 500 mM NaCl, wild-type enzyme Methanocaldococcus jannaschii

Metals/Ions

Metals/Ions Comment Organism Structure
Mg2+ 1:1 binding stoichiometry in absence of substrate at pH 8.0, activates, no binding to the enzyme but still weak activation without substrate at pH 6.5 Methanocaldococcus jannaschii
Mn2+ 1:1 binding stoichiometry in absence of substrate at pH 8.0, best activator, maximal activity at 10 mM and pH 8.0 Methanocaldococcus jannaschii
additional information enzyme is divalent metal ion-dependent, one metal ion binding mechanism, pH-dependence, kinetics, and thermodynamics for Mg2+, Mn2+, wild-type and mutant enzymes, substrate is involved in metal ion positioning and binding, Ca2+ and Ba2+ cannot substitute for Mn2+ or Mg2+ Methanocaldococcus jannaschii

Organism

Organism UniProt Comment Textmining
Methanocaldococcus jannaschii
-
 type 2 enzyme
-

Purification (Commentary)

Purification (Comment) Organism
recombinant wild-type and mutant enzymes from Escherichia coli, partially Methanocaldococcus jannaschii

Reaction

Reaction Comment Organism Reaction ID
Endonucleolytic cleavage to a 5'-phosphomonoester Asp149 is essential for catalytic activity, Asp7, Glu8 and Asp112 are invovled in metal ion binding Methanocaldococcus jannaschii
a

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
additional information no activity with dT36 and polyA Methanocaldococcus jannaschii ?
-
 ?
polyA*dT36 + H2O
-
 Methanocaldococcus jannaschii ?
-
 ?
polyA*dT36 hybrid + H2O
-
 Methanocaldococcus jannaschii ?
-
 ?
RNA*DNA hybrid + H2O specifically degrades the RNA moiety Methanocaldococcus jannaschii 5'-phospho-3'-hydroxyoligonucleotides
-
 ?

Synonyms

Synonyms Comment Organism
RNase H
-
 Methanocaldococcus jannaschii
RNase HII
-
 Methanocaldococcus jannaschii

Turnover Number [1/s]

Turnover Number Minimum [1/s] Turnover Number Maximum [1/s] Substrate Comment Organism Structure
0.11
-
 polyA*dT36 pH 8.0, 500 mM NaCl, wild-type enzyme Methanocaldococcus jannaschii
0.64
-
 polyA*dT36 pH 8.0, 50 mM NaCl, wild-type enzyme Methanocaldococcus jannaschii

pH Optimum

pH Optimum Minimum pH Optimum Maximum Comment Organism
8
-
 at 10 mM Mn2+ or Mg2+, wild-type enzyme Methanocaldococcus jannaschii

pH Range

pH Minimum pH Maximum Comment Organism
6.5 8 in presence of 10 mM Mn2+ the wild-type enzyme shows maximal activity at pH 8.0, 58% activity at pH 6.5, no activity at pH 5.5 Methanocaldococcus jannaschii