PDBsum entry 3k0h

Protein binding

PDB id: 3k0h

Contents

Protein chain

211 a.a. *

Ligands

SEP-PRO-THR-PHE-NH2

Metals

_NI

_CL

Waters ×18

* Residue conservation analysis

PDB id:

3k0h

Name:

Protein binding

Title:

The crystal structure of brca1 brct in complex with a minimal recognition tetrapeptide with an amidated c-terminus

Structure:

Breast cancer type 1 susceptibility protein. Chain: a. Fragment: brct domain (unp residues 1646 to 1859). Synonym: ring finger protein 53. Engineered: yes. Phospho peptide. Chain: b. Engineered: yes

Source:

Homo sapiens. Human. Organism_taxid: 9606. Gene: brca1, rnf53. Expressed in: escherichia coli. Expression_system_taxid: 562. Synthetic: yes. Other_details: this sequence occurs naturally in humans in the bach1/brip1 protein. The peptide is chemically synthesized.

Resolution:

2.70Å R-factor: 0.250 R-free: 0.296

Authors:

S.J.Campbell,R.A.Edwards,J.N.Glover

Key ref:

S.J.Campbell et al. (2010). Comparison of the structures and peptide binding specificities of the BRCT domains of MDC1 and BRCA1. Structure, 18, 167-176. PubMed id: 20159462

Date:

24-Sep-09 Release date: 02-Mar-10

Protein chain

P38398  (BRCA1_HUMAN) -  Breast cancer type 1 susceptibility protein from Homo sapiens

Seq: 1863 a.a.

Struc: 211 a.a.

Enzyme reactions

• Enzyme class: E.C.2.3.2.27 - RING-type E3 ubiquitin transferase.
• Reaction: S-ubiquitinyl-[E2 ubiquitin-conjugating enzyme]-L-cysteine + [acceptor protein]-L-lysine = [E2 ubiquitin-conjugating enzyme]-L-cysteine + N₆- ubiquitinyl-[acceptor protein]-L-lysine

Structure 18:167-176 (2010)

PubMed id: 20159462

Comparison of the structures and peptide binding specificities of the BRCT domains of MDC1 and BRCA1.

S.J.Campbell, R.A.Edwards, J.N.Glover.

ABSTRACT

The tandem BRCT domains of BRCA1 and MDC1 facilitate protein signaling at DNA damage foci through specific interactions with serine-phosphorylated protein partners. The MDC1 BRCT binds pSer-Gln-Glu-Tyr-COO(-) at the C terminus of the histone variant gammaH2AX via direct recognition of the C-terminal carboxylate, while BRCA1 recognizes pSer-X-X-Phe motifs either at C-terminal or internal sites within target proteins. Using fluorescence polarization binding assays, we show that while both BRCTs prefer a free main chain carboxylate at the +3 position, this preference is much more pronounced in MDC1. Crystal structures of BRCA1 and MDC1 bound to tetrapeptide substrates reveal differences in the environment of conserved arginines (Arg1699 in BRCA1 and Arg1933 in MDC1) that determine the relative affinity for peptides with -COO(-) versus -CO-NH(2) termini. A mutation in MDC1 that induces a more BRCA1-like conformation relaxes the binding specificity, allowing the mutant to bind phosphopeptides lacking a -COO(-) terminus.