2ALZ

Ternary Complex of hPoli with DNA and dCTP

Summary for 2ALZ

• Entry DOI: 10.2210/pdb2alz/pdb
• Descriptor: 5'-D(*TP*GP*GP*GP*GP*TP*CP*CP*T)-3', 5'-D(*AP*GP*GP*AP*CP*CP*(DOC))-3', DNA polymerase iota, ... (6 entities in total)
• Functional Keywords: right handed, dna polymerase, ternary complex, template g. incoming dctp, hoogsteen base pair, transferase-dna complex, transferase/dna
• Biological source: Homo sapiens (human)
• Cellular location: Nucleus: Q9UNA4
• Total number of polymer chains: 3
• Total formula weight: 49407.04

Authors

Nair, D.T.,Johnson, R.E.,Prakash, L.,Prakash, S.,Aggarwal, A.K. (deposition date: 2005-08-08, release date: 2005-10-25, Last modification date: 2023-08-23)

Primary citation

Nair, D.T.,Johnson, R.E.,Prakash, L.,Prakash, S.,Aggarwal, A.K.
Human DNA Polymerase iota Incorporates dCTP Opposite Template G via a G.C+ Hoogsteen Base Pair.
Structure, 13:1569-1577, 2005

PubMed Abstract: Human DNA polymerase iota (hPoliota), a member of the Y family of DNA polymerases, differs in remarkable ways from other DNA polymerases, incorporating correct nucleotides opposite template purines with a much higher efficiency and fidelity than opposite template pyrimidines. We present here the crystal structure of hPoliota bound to template G and incoming dCTP, which reveals a G.C + Hoogsteen base pair in a DNA polymerase active site. We show that the hPoliota active site has evolved to favor Hoogsteen base pairing, wherein the template sugar is fixed in a cavity that reduces the C1'-C1' distance across the nascent base pair from approximately 10.5 A in other DNA polymerases to 8.6 A in hPoliota. The rotation of G from anti to syn is then largely in response to this curtailed C1'-C1' distance. A G.C+ Hoogsteen base pair suggests a specific mechanism for hPoliota's ability to bypass N(2)-adducted guanines that obstruct replication.

PubMed: 16216587
DOI: 10.1016/j.str.2005.08.010

Experimental method

X-RAY DIFFRACTION (2.5 Å)