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Literature summary for 2.7.7.7 extracted from

  • Eoff, R.L.; Irimia, A.; Angel, K.C.; Egli, M.; Guengerich, F.P.
    Hydrogen bonding of 7,8-dihydro-8-oxodeoxyguanosine with a charged residue in the little finger domain determines miscoding events in Sulfolobus solfataricus DNA polymerase Dpo4 (2007), J. Biol. Chem., 282, 19831-19843.
    View publication on PubMed

Cloned(Commentary)

Cloned (Comment) Organism
expression in Escherichia coli Saccharolobus solfataricus

Crystallization (Commentary)

Crystallization (Comment) Organism
crystallization of mutant enzymes R332A and R332E in complex with DNA and dGTP (R332E(8-oxoG:A), R332E(8-oxoG:C), R332A(8-oxoG:A) and R332A(8-oxoG:C)). The R332E(8-oxoG:C) structure is crystallized by the hanging drop vapor diffusion technique, using a mixture of 14% polyethylene glycol 4000 (w/v), 0.1 M calcium acetate, and 20 mM HEPES (pH 7.3) as reservoir Saccharolobus solfataricus

Protein Variants

Protein Variants Comment Organism
R322H the His332 mutant exhibits faster forward rate constants relative to wild-type Dpo4. The kpol values for the His332 mutant incorporation opposite G and 8-oxoG are 3.6- and 4.6fold faster than for wild-type Dpo4. The nucleotide binding affinity trend is opposite that of wild-type Dpo4, Glu332, and Leu332, with tighter dCTP binding during bypass of G. As in the case of Ala332, the kinetic analysis indicates that His332 inserts dCTP opposite G with slightly greater efficiency than opposite 8-oxoG Saccharolobus solfataricus
R322L kpol (forward rate of polymerization) values for the Leu332 mutant incorporation opposite G and 8-oxoG are 4.1- and 1.9fold higher than those for wild-type Dpo4. The Leu332 mutant is about 2fold more efficient at incorporation of dCTP opposite 8-oxoG compared with G Saccharolobus solfataricus
R331A/R322A mutant has lower forward rate constants relative to wild-type enzyme for both G and 8-oxoG. The double mutant-catalyzed insertion of dCTP opposite 8-oxoG is about 4fold higher than dCTP insertion opposite G. The measured binding affinity of dCTP is tighter than that of wild-type Dpo4 for unmodified DNA, but the binding affinity of dCTP opposite 8-oxoG is similar to that observed for wild-type enzyme. The catalytic efficiency for dCTP incorporation increases about 4fold for unmodified DNA and decreases about 2fold for 8-oxoG-modified DNA. The mutant fails to incorporate dATP opposite 8-oxoG in the presteady-state experiments. It inserts dCTP opposite 8-oxoG with an about 200fold greater efficiency than it does dATP and the steady-state efficiency of dATP incorporation is decreased about 27fold relative to the wild-type enzyme Saccharolobus solfataricus
R332A mutant enzyme displays a higher affinity (lower KD,dCTP) for dCTP when bound to the unmodified DNA compared with the KD,dCTP measured for mutant-catalyzed incorporation of dCTP opposite 8-oxoG. Wild-type enzyme shows a greater affinity for dCTP opposite to 8-oxoG-modified DNA. The catalytic efficiency of the mutant is 23fold higher at incorporation of C opposite G and 1.2fold lower than wild-type enzyme in dCTP incorporation opposite 8-oxoG Saccharolobus solfataricus
R332E mutant enzyme retains fidelity against bypass of 7,8-dihydro-8-oxodeoxyguanosine (8-oxoG) that is similar to wild enzyme. A crystal structure of the mutant and 8-oxoG:C pair reveals water-mediated hydrogen bonds between Glu332 and the O-8 atom of 8-oxoG. The kpol (forward rate of polymerization) value for dCTP incorporation opposite G is 4.8fold higher than for wild-type enzyme. The kpol (forward rates of polymerization) value for dCTP incorporation opposite 8-oxoG is 3.5fold higher than wild-type enzyme insertion of dCTP opposite 8-oxoG. The catalytic efficiency of the Glu332 mutant is 2.3fold greater than wild-type Dpo4 for dCTP incorporation opposite G but 1.7fold less efficient than wild-type Dpo4 for incorporation opposite 8-oxoG Saccharolobus solfataricus

Natural Substrates/ Products (Substrates)

Natural Substrates Organism Comment (Nat. Sub.) Natural Products Comment (Nat. Pro.) Rev. Reac.
deoxynucleoside triphosphate + DNAn Saccharolobus solfataricus
-
diphosphate + DNAn+1
-
?
deoxynucleoside triphosphate + DNAn Saccharolobus solfataricus P2
-
diphosphate + DNAn+1
-
?

Organism

Organism UniProt Comment Textmining
Saccharolobus solfataricus Q97W02
-
-
Saccharolobus solfataricus P2 Q97W02
-
-

Purification (Commentary)

Purification (Comment) Organism
-
Saccharolobus solfataricus

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
deoxynucleoside triphosphate + DNAn
-
Saccharolobus solfataricus diphosphate + DNAn+1
-
?
deoxynucleoside triphosphate + DNAn
-
Saccharolobus solfataricus P2 diphosphate + DNAn+1
-
?

Synonyms

Synonyms Comment Organism
DNA polymerase IV
-
Saccharolobus solfataricus
Dpo4
-
Saccharolobus solfataricus

kcat/KM [mM/s]

kcat/KM Value [1/mMs-1] kcat/KM Value Maximum [1/mMs-1] Substrate Comment Organism Structure
additional information
-
additional information transient-state kinetic analysis of Dpo4 mutants and dATP Incorporation opposite 8-oxoG.Transient-state kinetic analysis of Dpo4 mutants and dCTP incorporation opposite 8-oxoG Saccharolobus solfataricus