PDBsum entry 4b8c

Hydrolase/cell cycle

PDB id: 4b8c

Contents

Protein chains

267 a.a.

233 a.a.

318 a.a.

210 a.a.

PDB id:

4b8c

Name:

Hydrolase/cell cycle

Title:

Nuclease module of the yeast ccr4-not complex

Structure:

Poly(a) ribonuclease pop2. Chain: a, c, e, f. Fragment: nuclease domain, residues 146-433. Synonym: pop2, ccr4-associated factor 1. Engineered: yes. General negative regulator of transcription subunit 1. Chain: b, g, h, i. Fragment: mif4g, residues 755-1000. Synonym: not1, cell division cycle protein 39.

Source:

Saccharomyces cerevisiae. Baker's yeast. Organism_taxid: 559292. Strain: s288c. Expressed in: spodoptera frugiperda. Expression_system_taxid: 7108. Saccharomyces cerevisiae s288c. Expressed in: escherichia coli. Expression_system_taxid: 511693.

Resolution:

3.41Å R-factor: 0.235 R-free: 0.270

Authors:

J.Basquin,E.Conti

Key ref:

J.Basquin et al. (2012). Architecture of the nuclease module of the yeast Ccr4-not complex: the Not1-Caf1-Ccr4 interaction. Mol Cell, 48, 207-218. PubMed id: 22959269

Date:

26-Aug-12 Release date: 21-Nov-12

Protein chains

P39008  (POP2_YEAST) -  Poly(A) ribonuclease POP2 from Saccharomyces cerevisiae (strain ATCC 204508 / S288c)

Seq: 433 a.a.

Struc: 267 a.a.

Protein chains

P25655  (NOT1_YEAST) -  General negative regulator of transcription subunit 1 from Saccharomyces cerevisiae (strain ATCC 204508 / S288c)

Seq: 2108 a.a.

Struc: 233 a.a.

Protein chains

P31384  (CCR4_YEAST) -  CCR4-Not complex 3'-5'-exoribonuclease subunit Ccr4 from Saccharomyces cerevisiae (strain ATCC 204508 / S288c)

Seq: 837 a.a.

Struc: 318 a.a.*

Protein chains

P31384  (CCR4_YEAST) -  CCR4-Not complex 3'-5'-exoribonuclease subunit Ccr4 from Saccharomyces cerevisiae (strain ATCC 204508 / S288c)

Seq: 837 a.a.

Struc: 210 a.a.

* PDB and UniProt seqs differ at 36 residue positions (black crosses)

Enzyme reactions

• Enzyme class: Chains A, C, D, E, F, J, K, L: E.C.3.1.13.4 - poly(A)-specific ribonuclease.
• Reaction: Exonucleolytic cleavage of poly(A) to 5'-AMP.

Mol Cell 48:207-218 (2012)

PubMed id: 22959269

Architecture of the nuclease module of the yeast Ccr4-not complex: the Not1-Caf1-Ccr4 interaction.

J.Basquin, V.V.Roudko, M.Rode, C.Basquin, B.Séraphin, E.Conti.

ABSTRACT

Shortening eukaryotic poly(A) tails represses mRNA translation and induces mRNA turnover. The major cytoplasmic deadenylase, the Ccr4-Not complex, is a conserved multisubunit assembly. Ccr4-Not is organized around Not1, a large scaffold protein that recruits two 3'-5' exoribonucleases, Caf1 and Ccr4. We report structural studies showing that the N-terminal arm of yeast Not1 has a HEAT-repeat structure with domains related to the MIF4G fold. A MIF4G domain positioned centrally within the Not1 protein recognizes Caf1, which in turn binds the LRR domain of Ccr4 and tethers the Ccr4 nuclease domain. The interactions that form the nuclease core of the Ccr4-Not complex are evolutionarily conserved. Their specific disruption affects cell growth and mRNA deadenylation and decay in vivo in yeast. Thus, the N-terminal arm of Not1 forms an extended platform reminiscent of scaffolding proteins like eIF4G and CBP80, and places the two nucleases in a pivotal position within the Ccr4-Not complex.