PDBsum entry 5bxh

Protein binding

PDB id: 5bxh

Contents

Protein chains

101 a.a.

PDB id:

5bxh

Name:

Protein binding

Title:

Crystal structure of pentameric kctd9 btb domain

Structure:

Btb/poz domain-containing protein kctd9. Chain: a, b, c, d, e. Fragment: btb domain residues 89-191. Engineered: yes

Source:

Homo sapiens. Human. Organism_taxid: 9606. Gene: kctd9. Expressed in: escherichia coli. Expression_system_taxid: 511693. Expression_system_variant: codon+.

Resolution:

2.76Å R-factor: 0.237 R-free: 0.280

Authors:

A.X.Ji,A.Chu,G.G.Prive

Key ref:

A.X.Ji et al. (2016). Structural Insights into KCTD Protein Assembly and Cullin3 Recognition. J Mol Biol, 428, 92. PubMed id: 26334369 DOI: 10.1016/j.jmb.2015.08.019

Date:

08-Jun-15 Release date: 02-Sep-15

Protein chains

Q7L273  (KCTD9_HUMAN) -  BTB/POZ domain-containing protein KCTD9 from Homo sapiens

Seq: 389 a.a.

Struc: 101 a.a.*

* PDB and UniProt seqs differ at 2 residue positions (black crosses)

DOI no: 10.1016/j.jmb.2015.08.019

J Mol Biol 428:92 (2016)

PubMed id: 26334369

Structural Insights into KCTD Protein Assembly and Cullin3 Recognition.

A.X.Ji, A.Chu, T.K.Nielsen, S.Benlekbir, J.L.Rubinstein, G.G.Privé.

ABSTRACT

Cullin3 (Cul3)-based ubiquitin E3 ligase complexes catalyze the transfer of ubiquitin from an E2 enzyme to target substrate proteins. In these assemblies, the C-terminal region of Cul3 binds Rbx1/E2-ubiquitin, while the N-terminal region interacts with various BTB (bric-à-brac, tramtrack, broad complex) domain proteins that serve as substrate adaptors. Previous crystal structures of the homodimeric BTB proteins KLHL3, KLHL11 and SPOP in complex with the N-terminal domain of Cul3 revealed the features required for Cul3 recognition in these proteins. A second class of BTB-domain-containing proteins, the KCTD proteins, is also Cul3 substrate adaptors, but these do not share many of the previously identified determinants for Cul3 binding. We report the pentameric crystal structures of the KCTD1 and KCTD9 BTB domains and identify plasticity in the KCTD1 rings. We find that the KCTD proteins 5, 6, 9 and 17 bind to Cul3 with high affinity, while the KCTD proteins 1 and 16 do not have detectable binding. Finally, we confirm the 5:5 assembly of KCTD9/Cul3 complexes by cryo-electron microscopy and provide a molecular rationale for BTB-mediated Cul3 binding specificity in the KCTD family.