PDBsum entry 3i4m

Transcription,transferase/DNA-RNA hybrid

PDB id: 3i4m

Contents

Protein chains

1429 a.a.

1125 a.a.

270 a.a.

187 a.a.

214 a.a.

88 a.a.

171 a.a.

137 a.a.

116 a.a.

65 a.a.

116 a.a.

47 a.a.

DNA/RNA

Metals

_ZN ×8

_MG

References listed in PDB file

Key reference

• Title: Molecular basis of transcriptional mutagenesis at 8-Oxoguanine.
• Authors: G.E.Damsma, P.Cramer.
• Ref.: J Biol Chem, 2009, 284, 31658-31663.
• PubMed id: 19758983

Abstract

Structure-function analysis has revealed the mechanism of yeast RNA polymerase II transcription at 8-oxoguanine (8-oxoG), the major DNA lesion resulting from oxidative stress. When polymerase II encounters 8-oxoG in the DNA template strand, it can misincorporate adenine, which forms a Hoogsteen bp with 8-oxoG at the active center. This requires rotation of the 8-oxoG base from the standard anti- to an uncommon syn-conformation, which likely occurs during 8-oxoG loading into the active site. The misincorporated adenine escapes intrinsic proofreading, resulting in transcriptional mutagenesis that is observed directly by mass spectrometric RNA analysis.