scholarly journals Biochemical evidence for the requirement of Hoogsteen base pairing for replication by human DNA polymerase  

2005 ◽  
Vol 102 (30) ◽  
pp. 10466-10471 ◽  
Author(s):  
R. E. Johnson ◽  
L. Prakash ◽  
S. Prakash
Keyword(s):  
Dna Polymerase ◽  
Base Pairing ◽  
Biochemical Evidence ◽  
Human Dna ◽  
Hoogsteen Base Pairing

Replication by human DNA polymerase-ι occurs by Hoogsteen base-pairing

Nature ◽  
2004 ◽  
Vol 430 (6997) ◽  
pp. 377-380 ◽  
Author(s):  
Deepak T. Nair ◽  
Robert E. Johnson ◽  
Satya Prakash ◽  
Louise Prakash ◽  
Aneel K. Aggarwal
Keyword(s):  
Dna Polymerase ◽  
Base Pairing ◽  
Human Dna ◽  
Hoogsteen Base Pairing ◽  
Dna Polymerase Ι

scholarly journals Mutagenesis mechanism of the major oxidative adenine lesion 7,8-dihydro-8-oxoadenine

2020 ◽  
Vol 48 (9) ◽  
pp. 5119-5134 ◽  
Author(s):  
Myong-Chul Koag ◽  
Hunmin Jung ◽  
Seongmin Lee
Keyword(s):  
Reactive Oxygen Species ◽  
Crystal Structures ◽  
Dna Polymerase ◽  
Dna Polymerases ◽  
Reactive Oxygen ◽  
Minor Groove ◽  
Oxygen Species ◽  
Base Pairing ◽  
Human Dna ◽  
Hoogsteen Base Pairing

Abstract Reactive oxygen species generate the genotoxic 8-oxoguanine (oxoG) and 8-oxoadenine (oxoA) as major oxidative lesions. The mutagenicity of oxoG is attributed to the lesion's ability to evade the geometric discrimination of DNA polymerases by adopting Hoogsteen base pairing with adenine in a Watson–Crick-like geometry. Compared with oxoG, the mutagenesis mechanism of oxoA, which preferentially induces A-to-C mutations, is poorly understood. In the absence of protein contacts, oxoA:G forms a wobble conformation, the formation of which is suppressed in the catalytic site of most DNA polymerases. Interestingly, human DNA polymerase η (polη) proficiently incorporates dGTP opposite oxoA, suggesting the nascent oxoA:dGTP overcomes the geometric discrimination of polη. To gain insights into oxoA-mediated mutagenesis, we determined crystal structures of polη bypassing oxoA. When paired with dGTP, oxoA adopted a syn-conformation and formed Hoogsteen pairing while in a wobble geometry, which was stabilized by Gln38-mediated minor groove contacts to oxoA:dGTP. Gln38Ala mutation reduced misinsertion efficiency ∼55-fold, indicating oxoA:dGTP misincorporation was promoted by minor groove interactions. Also, the efficiency of oxoA:dGTP insertion by the X-family polβ decreased ∼380-fold when Asn279-mediated minor groove contact to dGTP was abolished. Overall, these results suggest that, unlike oxoG, oxoA-mediated mutagenesis is greatly induced by minor groove interactions.

Roles of the active site residues and metal cofactors in noncanonical base-pairing during catalysis by human DNA polymerase iota

DNA Repair ◽  
2014 ◽  
Vol 22 ◽  
pp. 67-76 ◽  
Author(s):  
Alena V. Makarova ◽  
Artem Ignatov ◽  
Nataliya Miropolskaya ◽  
Andrey Kulbachinskiy
Keyword(s):  
Dna Polymerase ◽  
Active Site ◽  
Active Site Residues ◽  
Base Pairing ◽  
Dna Polymerase Iota ◽  
Human Dna ◽  
Metal Cofactors

scholarly journals Preferential Incorporation of G Opposite Template T by the Low-Fidelity Human DNA Polymerase ι

2000 ◽  
Vol 20 (19) ◽  
pp. 7099-7108 ◽  
Author(s):  
Yanbin Zhang ◽  
Fenghua Yuan ◽  
Xiaohua Wu ◽  
Zhigang Wang
Keyword(s):  
Dna Synthesis ◽  
Dna Polymerase ◽  
Polymerase Activity ◽  
Abasic Site ◽  
Base Pairing ◽  
Base Pairs ◽  
Dna Lesion ◽  
Biological Source ◽  
Human Dna ◽  
Base Selection

ABSTRACT DNA polymerase activity is essential for replication, recombination, repair, and mutagenesis. All DNA polymerases studied so far from any biological source synthesize DNA by the Watson-Crick base-pairing rule, incorporating A, G, C, and T opposite the templates T, C, G, and A, respectively. Non-Watson-Crick base pairs would lead to mutations. In this report, we describe the ninth human DNA polymerase, Polι, encoded by the RAD30B gene. We show that human Polι violates the Watson-Crick base-pairing rule opposite template T. During base selection, human Polι preferred T-G base pairing, leading to G incorporation opposite template T. The resulting T-G base pair was less efficiently extended by human Polι compared to the Watson-Crick base pairs. Consequently, DNA synthesis frequently aborted opposite template T, a property we designated the T stop. This T stop restricted human Polι to a very short stretch of DNA synthesis. Furthermore, kinetic analyses show that human Polι copies template C with extraordinarily low fidelity, misincorporating T, A, and C with unprecedented frequencies of 1/9, 1/10, and 1/11, respectively. Human Polι incorporated one nucleotide opposite a template abasic site more efficiently than opposite a template T, suggesting a role for human Polι in DNA lesion bypass. The unique features of preferential G incorporation opposite template T and T stop suggest that DNA Polι may additionally play a specialized function in human biology.

scholarly journals Replication past a trans-4-Hydroxynonenal Minor-Groove Adduct by the Sequential Action of Human DNA Polymerases ι and κ

2006 ◽  
Vol 26 (1) ◽  
pp. 381-386 ◽  
Author(s):  
William T. Wolfle ◽  
Robert E. Johnson ◽  
Irina G. Minko ◽  
R. Stephen Lloyd ◽  
Satya Prakash ◽  
...  
Keyword(s):  
Dna Polymerases ◽  
Minor Groove ◽  
Structural Features ◽  
Lesion Site ◽  
Base Pairing ◽  
General Applicability ◽  
Sequential Action ◽  
Human Dna ◽  
Hoogsteen Base Pairing ◽  
Dna Polymerase Ι

ABSTRACT The X-ray crystal structure of human DNA polymerase ι (Polι) has shown that it differs from all known Pols in its dependence upon Hoogsteen base pairing for synthesizing DNA. Hoogsteen base pairing provides an elegant mechanism for synthesizing DNA opposite minor-groove adducts that present a severe block to synthesis by replicative DNA polymerases. Germane to this problem, a variety of DNA adducts form at the N2 minor-groove position of guanine. Previously, we have shown that proficient and error-free replication through the γ-HOPdG (γ-hydroxy-1,N 2-propano-2′-deoxyguanosine) adduct, which is formed from the reaction of acrolein with the N2 of guanine, is mediated by the sequential action of human Polι and Polκ, in which Polι incorporates the nucleotide opposite the lesion site and Polκ carries out the subsequent extension reaction. To test the general applicability of these observations to other adducts formed at the N2 position of guanine, here we examine the proficiency of human Polι and Polκ to synthesize past stereoisomers of trans-4-hydroxy-2-nonenal-deoxyguanosine (HNE-dG). Even though HNE- and acrolein-modified dGs share common structural features, due to their increased size and other structural differences, HNE adducts are potentially more blocking for replication than γ-HOPdG. We show here that the sequential action of Polι and Polκ promotes efficient and error-free synthesis through the HNE-dG adducts, in which Polι incorporates the nucleotide opposite the lesion site and Polκ performs the extension reaction.

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