| Structural highlights
Function
[POLI_HUMAN] Error-prone DNA polymerase specifically involved in DNA repair. Plays an important role in translesion synthesis, where the normal high-fidelity DNA polymerases cannot proceed and DNA synthesis stalls. Favors Hoogsteen base-pairing in the active site. Inserts the correct base with high-fidelity opposite an adenosine template. Exhibits low fidelity and efficiency opposite a thymidine template, where it will preferentially insert guanosine. May play a role in hypermutation of immunogobulin genes. Forms a Schiff base with 5'-deoxyribose phosphate at abasic sites, but may not have lyase activity.[1] [2] [3] [4] [5] [6] [7]
Publication Abstract from PubMed
N1-methyl-deoxyadenosine (1-MeA) is formed by methylation of deoxyadenosine at the N1 atom. 1-MeA presents a block to replicative DNA polymerases due to its inability to participate in Watson-Crick (W-C) base pairing. Here we determine how human DNA polymerase-iota (Poliota) promotes error-free replication across 1-MeA. Steady state kinetic analyses indicate that Poliota is ~100 fold more efficient in incorporating the correct nucleotide T versus the incorrect nucleotide C opposite 1-MeA. To understand the basis of this selectivity, we determined ternary structures of Poliota bound to template 1-MeA and incoming dTTP or dCTP. In both structures, template 1-MeA rotates to the syn conformation but pairs differently with dTTP versus dCTP. Thus, whereas dTTP partakes in stable Hoogsteen base pairing with 1-MeA, dCTP fails to gain a "foothold" and is largely disordered. Together, our kinetic and structural studies show how Poliota maintains discrimination between correct and incorrect incoming nucleotide opposite 1-MeA in preserving genome integrity.
Mechanism of error-free DNA synthesis across N1-methyl-deoxyadenosine by human DNA polymerase-iota.,Jain R, Choudhury JR, Buku A, Johnson RE, Prakash L, Prakash S, Aggarwal AK Sci Rep. 2017 Mar 8;7:43904. doi: 10.1038/srep43904. PMID:28272441[8]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Tissier A, Frank EG, McDonald JP, Iwai S, Hanaoka F, Woodgate R. Misinsertion and bypass of thymine-thymine dimers by human DNA polymerase iota. EMBO J. 2000 Oct 2;19(19):5259-66. PMID:11013228 doi:http://dx.doi.org/10.1093/emboj/19.19.5259
- ↑ Bebenek K, Tissier A, Frank EG, McDonald JP, Prasad R, Wilson SH, Woodgate R, Kunkel TA. 5'-Deoxyribose phosphate lyase activity of human DNA polymerase iota in vitro. Science. 2001 Mar 16;291(5511):2156-9. PMID:11251121 doi:http://dx.doi.org/10.1126/science.1058386
- ↑ Frank EG, Tissier A, McDonald JP, Rapic-Otrin V, Zeng X, Gearhart PJ, Woodgate R. Altered nucleotide misinsertion fidelity associated with poliota-dependent replication at the end of a DNA template. EMBO J. 2001 Jun 1;20(11):2914-22. PMID:11387224 doi:http://dx.doi.org/10.1093/emboj/20.11.2914
- ↑ Faili A, Aoufouchi S, Flatter E, Gueranger Q, Reynaud CA, Weill JC. Induction of somatic hypermutation in immunoglobulin genes is dependent on DNA polymerase iota. Nature. 2002 Oct 31;419(6910):944-7. PMID:12410315 doi:http://dx.doi.org/10.1038/nature01117
- ↑ Haracska L, Prakash L, Prakash S. A mechanism for the exclusion of low-fidelity human Y-family DNA polymerases from base excision repair. Genes Dev. 2003 Nov 15;17(22):2777-85. PMID:14630940 doi:10.1101/gad.1146103
- ↑ Washington MT, Minko IG, Johnson RE, Wolfle WT, Harris TM, Lloyd RS, Prakash S, Prakash L. Efficient and error-free replication past a minor-groove DNA adduct by the sequential action of human DNA polymerases iota and kappa. Mol Cell Biol. 2004 Jul;24(13):5687-93. PMID:15199127 doi:http://dx.doi.org/10.1128/MCB.24.13.5687-5693.2004
- ↑ Nair DT, Johnson RE, Prakash S, Prakash L, Aggarwal AK. Replication by human DNA polymerase-iota occurs by Hoogsteen base-pairing. Nature. 2004 Jul 15;430(6997):377-80. PMID:15254543 doi:10.1038/nature02692
- ↑ Jain R, Choudhury JR, Buku A, Johnson RE, Prakash L, Prakash S, Aggarwal AK. Mechanism of error-free DNA synthesis across N1-methyl-deoxyadenosine by human DNA polymerase-iota. Sci Rep. 2017 Mar 8;7:43904. doi: 10.1038/srep43904. PMID:28272441 doi:http://dx.doi.org/10.1038/srep43904
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