Molecular Mechanism of SSR128129E, an Extracellularly Acting, Small-Molecule, Allosteric Inhibitor of FGF Receptor Signaling.
Cancer Cell. 2016 Jul 11;30(1):176-178
Authors: Herbert C, Schieborr U, Saxena K, Juraszek J, De Smet F, Alcouffe C, Bianciotto M, Saladino G, Sibrac D, Kudlinzki D, Sreeramulu S, Brown A, Rigon P, Herault JP, Lassalle G, Blundell TL, Rousseau F, Gils A, Schymkowitz J, Tompa P, Herbert JM, Carmeliet P, Gervasio FL, Schwalbe H, Bono F
PMID: 27479031 [PubMed - as supplied by publisher]
ATP half-sites in RadA and RAD51 recombinases bind nucleotides.
FEBS Open Bio. 2016 May;6(5):372-85
Authors: Marsh ME, Scott DE, Ehebauer MT, Abell C, Blundell TL, Hyvönen M
Homologous recombination is essential for repair of DNA double-strand breaks. Central to this process is a family of recombinases, including archeal RadA and human RAD51, which form nucleoprotein filaments on damaged single-stranded DNA ends and facilitate their ATP-dependent repair. ATP binding and hydrolysis are dependent on the formation of a nucleoprotein filament comprising RadA/RAD51 and single-stranded DNA, with ATP bound between adjacent protomers. We demonstrate that truncated, monomeric Pyrococcus furiosus RadA and monomerised human RAD51 retain the ability to bind ATP and other nucleotides with high affinity. We present crystal structures of both apo and nucleotide-bound forms of monomeric RadA. These structures reveal that while phosphate groups are tightly bound, RadA presents a shallow, poorly defined binding surface for the nitrogenous bases of nucleotides. We suggest that RadA monomers would be constitutively bound to nucleotides in the cell and that the bound nucleotide might play a structural role in filament assembly.
PMID: 27419043 [PubMed]
mCSM-lig: quantifying the effects of mutations on protein-small molecule affinity in genetic disease and emergence of drug resistance.
Sci Rep. 2016;6:29575
Authors: Pires DE, Blundell TL, Ascher DB
The ability to predict how a mutation affects ligand binding is an essential step in understanding, anticipating and improving the design of new treatments for drug resistance, and in understanding genetic diseases. Here we present mCSM-lig, a structure-guided computational approach for quantifying the effects of single-point missense mutations on affinities of small molecules for proteins. mCSM-lig uses graph-based signatures to represent the wild-type environment of mutations, and small-molecule chemical features and changes in protein stability as evidence to train a predictive model using a representative set of protein-ligand complexes from the Platinum database. We show our method provides a very good correlation with experimental data (up to ρ = 0.67) and is effective in predicting a range of chemotherapeutic, antiviral and antibiotic resistance mutations, providing useful insights for genotypic screening and to guide drug development. mCSM-lig also provides insights into understanding Mendelian disease mutations and as a tool for guiding protein design. mCSM-lig is freely available as a web server at http://structure.bioc.cam.ac.uk/mcsm_lig.
PMID: 27384129 [PubMed - as supplied by publisher]
Structure of BRCA1-BRCT/Abraxas Complex Reveals Phosphorylation-Dependent BRCT Dimerization at DNA Damage Sites.
Mol Cell. 2016 Feb 4;61(3):434-48
Authors: Wu Q, Paul A, Su D, Mehmood S, Foo TK, Ochi T, Bunting EL, Xia B, Robinson CV, Wang B, Blundell TL
BRCA1 accumulation at DNA damage sites is an important step for its function in the DNA damage response and in DNA repair. BRCA1-BRCT domains bind to proteins containing the phosphorylated serine-proline-x-phenylalanine (pSPxF) motif including Abraxas, Bach1/FancJ, and CtIP. In this study, we demonstrate that ionizing radiation (IR)-induces ATM-dependent phosphorylation of serine 404 (S404) next to the pSPxF motif. Crystal structures of BRCT/Abraxas show that phosphorylation of S404 is important for extensive interactions through the N-terminal sequence outside the pSPxF motif and leads to formation of a stable dimer. Mutation of S404 leads to deficiency in BRCA1 accumulation at DNA damage sites and cellular sensitivity to IR. In addition, two germline mutations of BRCA1 are found to disrupt the dimer interface and dimer formation. Thus, we demonstrate a mechanism involving IR-induced phosphorylation and dimerization of the BRCT/Abraxas complex for regulating Abraxas-mediated recruitment of BRCA1 in response to IR.
PMID: 26778126 [PubMed - indexed for MEDLINE]