5lb4

<StructureSection load='5lb4' size='340' side='right' caption='[[5lb4]], [[Resolution|resolution]] 1.98&Aring;' scene=''>

<table><tr><td colspan='2'>[[5lb4]] is a 1 chain structure. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=5LB4 OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=5LB4 FirstGlance]. <br>

</td></tr><tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=5lb4 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=5lb4 OCA], [http://pdbe.org/5lb4 PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=5lb4 RCSB], [http://www.ebi.ac.uk/pdbsum/5lb4 PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=5lb4 ProSAT]</span></td></tr>

[[http://www.uniprot.org/uniprot/RADA_PYRFU RADA_PYRFU]] Involved in DNA repair and in homologous recombination. Binds and assemble on single-stranded DNA to form a nucleoprotein filament. Hydrolyzes ATP in a ssDNA-dependent manner and promotes DNA strand exchange between homologous DNA molecules.

Protein-protein interactions (PPIs) are increasingly important targets for drug discovery. Efficient fragment-based drug discovery approaches to tackle PPIs are often stymied by difficulties in the production of stable, unliganded target proteins. Here, we report an approach that exploits protein engineering to 'humanise' thermophilic archeal surrogate proteins as targets for small molecule inhibitor discovery, and exemplify this approach in the development of inhibitors against the PPI between the recombinase RAD51 and tumour suppressor BRCA2. As human RAD51 has proved impossible to produce in a form that is compatible with the requirements of fragment-based drug discovery, we have developed a surrogate protein system using RadA from Pyrococcus furiosus. Using a monomerised RadA as our starting point, we have adopted two parallel and mutually instructive approaches to mimic the human enzyme: firstly by mutating RadA to increase sequence identity with RAD51 in the BRC repeat binding sites, and secondly by generating a chimeric archaeal-human protein. Both approaches generate proteins that interact with a BRC4 repeat with affinity and stoichiometry comparable to human RAD51. Stepwise humanisation has also allowed us to elucidate the determinants of RAD51 binding to BRC repeats and the contributions of key interacting residues to this interaction. These surrogate proteins have enabled the development of biochemical and biophysical assays in our ongoing fragment-based small molecule inhibitor programme and they have allowed us to determine hundreds of liganded structures in support of our structure-guided design process, demonstrating the feasibility and advantages of using archeal surrogates to overcome difficulties in handling human proteins.

 

== References ==

[[Category: Abell, C]]

[[Category: Blundell, TL]]

[[Category: Fischer, G]]

[[Category: Hyvonen, M]]

[[Category: Marsh, M]]

[[Category: Morgan, M]]

[[Category: Moschetti, T]]

[[Category: Ng, H]]

[[Category: Scott, D]]

[[Category: Sharpe, T]]

[[Category: Skidmore, J]]

[[Category: Venkitaraman, A]]

[[Category: Hydrolase]]