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BACCHUS. B reeding A ctivity- C lustered C hemical H yperstruct U re S. Nathan Brown. Department of Information Studies University of Sheffield. Overview. Chemical hyperstructures Including activity information Validation experiments Colouring molecules by weights
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BACCHUS Breeding Activity-Clustered Chemical HyperstructUreS Nathan Brown Department of Information Studies University of Sheffield
Overview • Chemical hyperstructures • Including activity information • Validation experiments • Colouring molecules by weights • Possible applications • Conclusions & further work
Introduction • Traditional QSAR approaches limited to: • Small datasets • Similar structural classes • Quantitative data • High-throughput screening tends to produce: • Large datasets • Diverse structural classes • Qualitative data
Chemical Hyperstructures • Pseudo-molecule representing a library • Sequential mapping of molecules • Minimise structural redundancy • Maximum overlap set • Combinatorial explosion • Genetic algorithms
Hyperstructure Generation Input molecule: Hyperstructure:
Introducing BACCHUS Breeding Activity-Clustered Chemical HyperstructUreS • Correlation between structure & activity • Assign activity and inactivity weights to nodes and edges of hyperstructure • Weights reinforced through generation • Activity = acts / (acts + inacts)
Inactive Active Active Inactive Including Activity Input molecule: Hyperstructure:
Methodology & validation • 2,000 hyperstructures generated with: • 50 actives and 50 inactives from NCI AIDS • 1,000 from known activities • 1,000 from randomised activities • Summarise hyperstructures from both sets • Distributions and t-scores comparing: • Known activities against randomised activities
Node Activities t = 54.57
Node Inactivities t = 13.80
Further Validation [4 activity classes from the IDAlert database]
Active Molecules activeinactive
Inactive Molecules activeinactive
Possible Applications • Identification of common active features within the hyperstructure • cf. MCS-based pharmacophore detection methods • Use active subgraphs for similarity searching • cf. modal fingerprints • Score unknown molecules against an AWCH • cf. fragment-based substructural analysis
Conclusions & Further Work • BACCHUS presented as approach for: • Analysing structural & bioactivity data • Visualisation of induced molecules • Current & future work • Substructural analysis • Parallel implementation
Acknowledgements • Peter Willett and David J. Wilton • University of Sheffield • Richard A. Lewis • Eli Lilly and Company • CASE Award with EPSRC and Eli Lilly