PDBsum entry: 2ado

Cell cycle

PDB id: 2ado

Contents

Protein chains

194 a.a. *

Waters ×256

* Residue conservation analysis

PDB id:

2ado

Name:

Cell cycle

Title:

Crystal structure of the brct repeat region from the mediator of DNA damage checkpoint protein 1, mdc1

Structure:

Mediator of DNA damage checkpoint protein 1. Chain: a, b. Fragment: residues 1891-2086. Synonym: nuclear factor with brct domains 1. Engineered: yes

Source:

Homo sapiens. Human. Organism_taxid: 9606. Gene: mdc1, kiaa0170, nfbd1. Expressed in: escherichia coli. Expression_system_taxid: 562.

Resolution:

1.45Å R-factor: 0.195 R-free: 0.212

Authors:

M.S.Lee,R.A.Edwards,G.L.Thede,J.N.Glover

Key ref:

M.S.Lee et al. (2005). Structure of the BRCT repeat domain of MDC1 and its specificity for the free COOH-terminal end of the gamma-H2AX histone tail. J Biol Chem, 280, 32053-32056. PubMed id: 16049003 DOI: 10.1074/jbc.C500273200

Date:

20-Jul-05 Release date: 02-Aug-05

Protein chains

Q14676  (MDC1_HUMAN) -  Mediator of DNA damage checkpoint protein 1

Seq: 2089 a.a.

Struc: 194 a.a.

 Gene Ontology (GO) functional annotation 

• Cellular component: intracellular (1 term)

DOI no: 10.1074/jbc.C500273200

J Biol Chem 280:32053-32056 (2005)

PubMed id: 16049003

Structure of the BRCT repeat domain of MDC1 and its specificity for the free COOH-terminal end of the gamma-H2AX histone tail.

M.S.Lee, R.A.Edwards, G.L.Thede, J.N.Glover.

ABSTRACT

MDC1 (mediator of DNA damage checkpoint protein 1) regulates the recognition and repair of DNA double strand breaks in mammalian cells through its interactions with nuclear foci containing the COOH-terminally phosphorylated form of the histone variant, H2AX. Here we demonstrate that the tandem BRCT repeats of MDC1 directly bind to the phosphorylated tail of H2AX-Ser(P)-Gln-Glu-Tyr, in a manner that is critically dependent on the free carboxylate group of the COOH-terminal Tyr residue. We have determined the x-ray crystal structure of the MDC1 BRCT repeats at 1.45 Angstroms resolution. By a comparison with the structure of the BRCA1 BRCT bound to a phosphopeptide, we suggest that two arginine residues in MDC1, Arg(1932) and Arg(1933) may recognize the COOH terminus of the peptide as well as the penultimate Glu of H2AX, while Gln(2013) may provide additional specificity for the COOH-terminal Tyr.

Selected figure(s)

Figure 1.
FIGURE 1. The MDC1 BRCT domain specifically recognizes the free carboxyl terminus of the -H2AX tail. Shown are sample ITC experiments showing titration of the MDC1 BRCT domain with the -H2AX peptide bearing a free carboxylate at the COOH terminus (top panel) or an amidated COOH terminus (bottom panel). The titration curves (insets) were used to determine the dissociation constants. The K[d] values shown are the average of three independent experiments.

Figure 2.
FIGURE 2. Structure of the tandem BRCT repeats of MDC1. A, overview of the MDC1 BRCT structure (cyan) aligned with the structure of the BRCA1 BRCT (magenta) bound to an optimized phospho-peptide target (orange) (Protein Data Bank accession code 1T2V [PDB] ). B, details of the phosphopeptide recognition surfaces of BRCA1 and MDC1, colored as in A. Residues involved in peptide binding are labeled and shown as sticks. C, sequence alignment of the MDC1 and BRCA1 BRCT repeats. The secondary structure of MDC1 is indicated, and residues conserved in the phosphoserine binding pocket are highlighted in blue. Residues involved in the head-to-tail packing of the NH[2]- and COOH-terminal BRCT repeats are shaded in gray.

The above figures are reprinted by permission from the ASBMB: J Biol Chem (2005, 280, 32053-32056) copyright 2005.