Summary information and primary citation
- PDB-id
- 3h4b; SNAP-derived features in text and JSON formats;
DNAproDB
- Class
- replication-DNA
- Method
- X-ray (2.85 Å)
- Summary
- Ternary complex of human DNA polymerase iota with template u-t and incoming datp
- Reference
- Jain R, Nair DT, Johnson RE, Prakash L, Prakash S, Aggarwal AK (2009): "Replication across template T/U by human DNA polymerase-iota." Structure, 17, 974-980. doi: 10.1016/j.str.2009.04.011.
- Abstract
- Human DNA polymerase-iota (Poliota) incorporates correct nucleotides opposite template purines with a much higher efficiency and fidelity than opposite template pyrimidines. In fact, the fidelity opposite template T is so poor that Poliota inserts an incorrect dGTP approximately 10 times better than it inserts the correct dATP. We determine here how a template T/U is accommodated in the Poliota active site and why a G is incorporated more efficiently than an A. We show that in the absence of incoming dATP or dGTP (binary complex), template T/U exists in both syn and anti conformations, but in the presence of dATP or dGTP (ternary complexes), template T/U is predominantly in the anti conformation. We also show that dATP and dGTP insert differently opposite template T/U, and that the basis of selection of dGTP over dATP is a hydrogen bond between the N2 amino group of dGTP and Gln59 of Poliota.
