PDBsum entry 2q81

Transcription

PDB id: 2q81

Contents

Protein chain

114 a.a. *

Ligands

PG4

Waters ×239

* Residue conservation analysis

PDB id:

2q81

Name:

Transcription

Title:

Crystal structure of the miz-1 btb/poz domain

Structure:

Miz-1 protein. Chain: a, b, c, d. Fragment: btb domain, residues 2-115. Synonym: zinc finger and btb domain-containing protein 17, zinc finger protein 151, myc-interacting zinc finger protein. Engineered: yes

Source:

Homo sapiens. Human. Organism_taxid: 9606. Gene: zbtb17, miz1, znf151. Expressed in: escherichia coli. Expression_system_taxid: 562.

Resolution:

2.10Å R-factor: 0.184 R-free: 0.229

Authors:

M.A.Stead,C.H.Trinh,J.A.Garnett,S.B.Carr,T.A.Edwards,S.C.Wright

Key ref:

M.A.Stead et al. (2007). A beta-sheet interaction interface directs the tetramerisation of the Miz-1 POZ domain. J Mol Biol, 373, 820-826. PubMed id: 17880999 DOI: 10.1016/j.jmb.2007.08.026

Date:

08-Jun-07 Release date: 06-Nov-07

Protein chains

Q13105  (ZBT17_HUMAN) -  Zinc finger and BTB domain-containing protein 17 from Homo sapiens

Seq: 803 a.a.

Struc: 114 a.a.*

* PDB and UniProt seqs differ at 1 residue position (black cross)

DOI no: 10.1016/j.jmb.2007.08.026

J Mol Biol 373:820-826 (2007)

PubMed id: 17880999

A beta-sheet interaction interface directs the tetramerisation of the Miz-1 POZ domain.

M.A.Stead, C.H.Trinh, J.A.Garnett, S.B.Carr, A.J.Baron, T.A.Edwards, S.C.Wright.

ABSTRACT

The POZ/BTB domain is an evolutionarily conserved motif found in approximately 40 zinc-finger transcription factors (POZ-ZF factors). Several POZ-ZF factors are implicated in human cancer, and POZ domain interaction interfaces represent an attractive target for therapeutic intervention. Miz-1 (Myc-interacting zinc-finger protein) is a POZ-ZF factor that regulates DNA-damage-induced cell cycle arrest and plays an important role in human cancer by virtue of its interaction with the c-Myc and BCL6 oncogene products. The Miz-1 POZ domain mediates both self-association and the recruitment of non-POZ partners. POZ-ZF factors generally function as homodimers, although higher-order associations and heteromeric interactions are known to be physiologically important; crucially, the interaction interfaces in such large complexes have not been characterised. We report here the crystal structure of the Miz-1 POZ domain up to 2.1 A resolution. The tetrameric organisation of Miz-1 POZ reveals two types of interaction interface between subunits; an interface of alpha-helices resembles the dimerisation interface of reported POZ domain structures, whereas a novel beta-sheet interface directs the association of two POZ domain dimers. We show that the beta-sheet interface directs the tetramerisation of the Miz-1 POZ domain in solution and therefore represents a newly described candidate interface for the higher-order homo- and hetero-oligomerisation of POZ-ZF proteins in vivo.

Selected figure(s)

Figure 1.
Fig. 1. Structure of the Miz-1 POZ domain. (a) Ribbon representation of the Miz-1 POZ domain tetramer. Subunits A–D are indicated in different colours. The secondary structure elements of the A-chain and of the A:D interface are shown. The structure of the BCL6 POZ domain (PDB accession code 1r28) is shown for comparison; the box indicates the β1–β5′ beta-sheet of the BCL6 dimerisation interface that is absent in Miz-1 (positions on the partner chain of BCL6 are indicated with primes). The Miz-1 POZ domain (residues 2–115) was expressed as a glutathione S-transferase fusion protein in E. coli BL21(DE3)pLysS. The glutathione S-transferase tag was removed by cleavage with PreScission protease, and the Miz-1 POZ domain fragment was purified by chromatography on Q-Sepharose, Resource Q and Supadex 75. Crystals of the purified Miz-1 POZ domain were obtained by hanging-drop vapour diffusion against 20% polyethylene glycol 3350; 20% polyethylene glycol 400; 200 mM MgCl[2]; and 100 mM Hepes (pH 7.5). Details of plasmid construction, protein purification, X-ray data collection and structure determination are reported in Supplementary Data.^[20.]^, ^[21.]^, ^[22.]^, ^[23.]^, ^[24.]^, ^[25.]^, ^[26.]^ and ^[27.] (b) Superposition of POZ domain Cα atoms for Miz-1, BCL6, PLZF and LRF. Stereoimage of the superpositions of POZ domain dimers (BCL6, accession code 1r28; PLZF, accession code 1buo; LRF, accession code 2nn2; the Miz-1 dimer corresponds to chains A and B). Miz-1 (green), BCL6 (cyan), LRF (magenta), PLZF (yellow).

Figure 3.
Fig. 3. Electrostatic surface representation of the Miz-1 POZ domain. Both flat faces of the Miz-1 POZ tetramer are shown together with bottom and side surfaces; the bottom surfaces of the BCL6, PLZF and LRF POZ dimers are shown for comparison.

The above figures are reprinted by permission from Elsevier: J Mol Biol (2007, 373, 820-826) copyright 2007.

Figures were selected by an automated process.