| Structural highlights
4ebe is a 3 chain structure with sequence from Human. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
| | Ligands: | , , |
| NonStd Res: | |
| Related: | 1t3n, 2alz, 3gv5, 3gv7, 3gv8, 3h40, 4ebc, 4ebd |
| Gene: | POLI, RAD30B (HUMAN) |
| Activity: | DNA-directed DNA polymerase, with EC number 2.7.7.7 |
| Resources: | FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT |
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
Y-family DNA polymerases participate in replication stress and DNA damage tolerance mechanisms. The properties that allow these enzymes to copy past bulky adducts or distorted template DNA can result in a greater propensity for them to make mistakes. Of the four human Y-family members, human DNA polymerase iota (hpol iota) is the most error-prone. In the current study, we elucidate the molecular basis for improving the fidelity of hpol iota through use of the fixed-conformation nucleotide North-methanocarba-2'-deoxyadenosine triphosphate (N-MC-dATP). Three crystal structures were solved of hpol iota in complex with DNA containing a template 2'-deoxythymidine (dT) paired with an incoming dNTP or modified nucleotide triphosphate. The ternary complex of hpol iota inserting N-MC-dATP opposite dT reveals that the adenine ring is stabilized in the anti orientation about the pseudo-glycosyl torsion angle (chi), which mimics precisely the mutagenic arrangement of dGTP:dT normally preferred by hpol iota. The stabilized anti conformation occurs without notable contacts from the protein but likely results from constraints imposed by the bicyclo[3.1.0]hexane scaffold of the modified nucleotide. Unmodified dATP and South-MC-dATP each adopt syn glycosyl orientations to form Hoogsteen base pairs with dT. The Hoogsteen orientation exhibits weaker base stacking interactions and is less catalytically favorable than anti N-MC-dATP. Thus, N-MC-dATP corrects the error-prone nature of hpol iota by preventing the Hoog-steen base-pairing mode normally observed for hpol iota-catalyzed insertion of dATP opposite dT. These results provide a previously unrecognized means of altering the efficiency and the fidelity of a human translesion DNA polymerase.
A nucleotide analogue induced gain of function corrects the error-prone nature of human DNA polymerase iota.,Ketkar A, Zafar MK, Banerjee S, Marquez VE, Egli M, Eoff RL J Am Chem Soc. 2012 May 26. PMID:22632140[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
- ↑ Ketkar A, Zafar MK, Banerjee S, Marquez VE, Egli M, Eoff RL. A nucleotide analogue induced gain of function corrects the error-prone nature of human DNA polymerase iota. J Am Chem Soc. 2012 May 26. PMID:22632140 doi:10.1021/ja304176q
|
