5kt3

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Teranry complex of human DNA polymerase iota(26-445) inserting dCMPNPP opposite template G in the presence of Mn2+Teranry complex of human DNA polymerase iota(26-445) inserting dCMPNPP opposite template G in the presence of Mn2+

Structural highlights

5kt3 is a 3 chain structure with sequence from Homo sapiens and Synthetic construct. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:X-ray diffraction, Resolution 2.64Å
Ligands:,
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

DNA polymerase (pol) iota is a Y-family polymerase involved in translesion synthesis, exhibiting higher catalytic activity with Mn2+ than Mg2+. The human germline R96G variant impairs both Mn2+- and Mg2+-dependent activities of pol iota, while the Delta1-25 variant selectively enhances its Mg2+-dependent activity. We analyzed pre-steady-state kinetic and structural effects of these two metal ions and genetic variations on pol iota using pol iota core (residues 1-445) proteins. The presence of Mn2+ (0.15 mM) instead of Mg2+ (2 mM) caused a 770-fold increase in efficiency (kpol/Kd,dCTP) of pol iota for dCTP insertion opposite G, mainly due to a 450-fold decrease in Kd,dCTP. The R96G and Delta1-25 variants displayed a 53-fold decrease and a 3-fold increase, respectively, in kpol/Kd,dCTP for dCTP insertion opposite G with Mg2+ when compared to wild-type, substantially attenuated by substitution with Mn2+. Crystal structures of pol iota ternary complexes, including the primer terminus 3'-OH and a non-hydrolyzable dCTP analog opposite G with the active-site Mg2+ or Mn2+, revealed that Mn2+ achieves more optimal octahedral coordination geometry than Mg2+, with lower values in average coordination distance geometry in the catalytic metal A-site. Crystal structures of R96G revealed the loss of three H-bonds of residues Gly-96 and Tyr-93 with an incoming dNTP, due to the lack of an arginine as well as a destabilized Tyr-93 side chain secondary to the loss of a cation-pi interaction between both side chains. These results provide a mechanistic basis for alteration in pol iota catalytic function with coordinating metals and genetic variation.

Kinetic and Structural Impact of Metal Ions and Genetic Variations on Human DNA Polymerase iota.,Choi JY, Patra A, Yeom M, Lee YS, Zhang Q, Egli M, Guengerich FP J Biol Chem. 2016 Aug 23. pii: jbc.M116.748285. PMID:27555320[8]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

See Also

References

  1. ↑ 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
  2. ↑ 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
  3. ↑ 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
  4. ↑ 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
  5. ↑ 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
  6. ↑ 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
  7. ↑ 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
  8. ↑ Choi JY, Patra A, Yeom M, Lee YS, Zhang Q, Egli M, Guengerich FP. Kinetic and Structural Impact of Metal Ions and Genetic Variations on Human DNA Polymerase iota. J Biol Chem. 2016 Aug 23. pii: jbc.M116.748285. PMID:27555320 doi:http://dx.doi.org/10.1074/jbc.M116.748285

5kt3, resolution 2.64Å

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