PDBsum entry 4c2m

Transcription

PDB id: 4c2m

Contents

Protein chains

44 a.a.

103 a.a.

145 a.a.

54 a.a.

1521 a.a.

1182 a.a.

305 a.a.

58 a.a.

212 a.a.

100 a.a.

193 a.a.

131 a.a.

124 a.a.

69 a.a.

101 a.a.

108 a.a.

145 a.a.

59 a.a.

Ligands

SO4 ×2

Metals

_ZN ×14

Waters ×262

References listed in PDB file

Key reference

• Title: Rna polymerase I structure and transcription regulation.
• Authors: C.Engel, S.Sainsbury, A.C.Cheung, D.Kostrewa, P.Cramer.
• Ref.: Nature, 2013, 502, 650-655. [DOI no: 10.1038/nature12712]
• PubMed id: 24153182

Abstract

Transcription of ribosomal RNA by RNA polymerase (Pol) I initiates ribosome biogenesis and regulates eukaryotic cell growth. The crystal structure of Pol I from the yeast Saccharomyces cerevisiae at 2.8 Å resolution reveals all 14 subunits of the 590-kilodalton enzyme, and shows differences to Pol II. An 'expander' element occupies the DNA template site and stabilizes an expanded active centre cleft with an unwound bridge helix. A 'connector' element invades the cleft of an adjacent polymerase and stabilizes an inactive polymerase dimer. The connector and expander must detach during Pol I activation to enable transcription initiation and cleft contraction by convergent movement of the polymerase 'core' and 'shelf' modules. Conversion between an inactive expanded and an active contracted polymerase state may generally underlie transcription. Regulatory factors can modulate the core-shelf interface that includes a 'composite' active site for RNA chain initiation, elongation, proofreading and termination.