1j4p
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| Ligands: | |||||||
| Gene: | SPK1 OR RAD53 (Saccharomyces cerevisiae) | ||||||
| Resources: | FirstGlance, OCA, PDBsum, RCSB | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
NMR STRUCTURE OF THE FHA1 DOMAIN OF RAD53 IN COMPLEX WITH A RAD9-DERIVED PHOSPHOTHREONINE (AT T155) PEPTIDE
OverviewOverview
Rad53, a yeast checkpoint protein involved in regulating the repair of DNA damage, contains two forkhead-associated domains, FHA1 and FHA2. Previous combinatorial library screening has shown that FHA1 strongly selects peptides containing a pTXXD motif. Subsequent location of this motif within the sequence of Rad9, the target protein, coupled with spectroscopic analysis has led to identification of a tight binding sequence that is likely the binding site of FHA1: (188)SLEV(pT)EADATFVQ(200). We present solution structures of FHA1 in complex with this pT-peptide and with another Rad9-derived pT-peptide that has ca 30-fold lower affinity, (148)KKMTFQ(pT)PTDPLE(160). Both complexes showed intermolecular NOEs predominantly between three peptide residues (pT, +1, and +2 residues) and five FHA1 residues (S82, R83, S85, T106, and N107). Furthermore, the following interactions were implicated on the basis of chemical shift perturbations and structural analysis: the phosphate group of the pT residue with the side-chain amide group of N86 and the guanidino group of R70, and the carboxylate group of Asp (at the +3 position) with the guanidino group of R83. The generated structures revealed a similar binding mode adopted by these two peptides, suggesting that pT and the +3 residue Asp are the major contributors to binding affinity and specificity, while +1 and +2 residues could provide additional fine-tuning. It was also shown that FHA1 does not bind to the corresponding pS-peptides or a related pY-peptide. We suggest that differentiation between pT and pS-peptides by FHA1 can be attributed to hydrophobic interactions between the methyl group of the pT residue and the aliphatic protons of R83, S85, and T106 from FHA1.
About this StructureAbout this Structure
1J4P is a Protein complex structure of sequences from Saccharomyces cerevisiae. Full crystallographic information is available from OCA.
ReferenceReference
Solution structures of two FHA1-phosphothreonine peptide complexes provide insight into the structural basis of the ligand specificity of FHA1 from yeast Rad53., Yuan C, Yongkiettrakul S, Byeon IJ, Zhou S, Tsai MD, J Mol Biol. 2001 Nov 30;314(3):563-75. PMID:11846567
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