Genomics & Proteomics Based Drug Discovery

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  • 1.Genomics & Proteomics Based Drug DISCOVERY Dr. Basavaraj K. NanjwadeM.Pharm., Ph. D Associate Professor Department of Pharmaceutics KLE University BELGAUM 590010

2. Genomics

  • Genetic scientist isolate individual genes and determine their chemical composition, and ultimately to sequence entire genomes.
  • The sequencing of the human genome with the human genome project

3. Genome Sequencing

  • Gene number, exact locations, and functions
  • Gene regulation
  • DNA sequence organization
  • Chromosomal structure and organization
  • Noncoding DNA types, amount, distribution, information content, and functions
  • Coordination of gene expression, protein synthesis, and post-translational events
  • Interaction of proteins in complex molecular machines
  • Predicted vs experimentally determined gene function

4. Genome Sequencing

  • Evolutionary conservation among organisms
  • Protein conservation (structure and function)
  • Proteomes (total protein content and function) in organisms
  • Correlation of SNPs (Single nucleotide polymorphisms ) with health and disease
  • Disease-susceptibility prediction based on gene sequence variation
  • Genes involved in complex traits and multigene diseases
  • Complex systems biology including microbial consortia useful for environmental restoration
  • Developmental genetics, genomics

5. Genome Sequencing C = Cytosine, G = Guanine, A = Adenine and T = Thymine 6.

  • SBI* can be used to examine:
      • drugtargets(usually proteins)
      • binding ofligands
      • rational drug design
      • (benefits = saved time andRsRsRs )

Drug Discovery * SBI-Structural Bioinformatics 7.

  • Whats different?
  • Drug discovery process begins
  • with adisease(rather than a treatment)
  • Use disease model to pinpoint relevant genetic/biological components (i.e. possible drug targets)

ModernDrug Discovery NEW and IMPROVED! 8. Modern Drug Discovery

  • disease ->genetic/biological target
  • discovery of a lead molecule
          • - design assay to measure function oftarget
          • - use assay to look for modulators oftargets function
          • high throughput screen (HTS)
          • - to identify hits

9. Modern Drug Discovery

  • small molecule hits
  • manipulate structure to increase potency
  • *optimization of lead molecule into candidate drug*
  • fulfillment of required pharmacological properties:
  • potency, absorption, bioavailability, metabolism, safety
  • clinical trials

10. Interesting facts...

  • Over 90% of drugs entering clinical trials fail to make it to market
  • The average cost to bring a new drug to market is estimated at$770 million

11. Relating druggable targetsto disease...

  • Analysis of Pharmindustry reveals:
      • Over 400 proteins used as drug targets
      • Sequence analysis of these proteins shows that most targets fall within a few major gene families (GPCRs, kinases, proteases and peptidases)

12. Assessing Target Druggability

  • Once a target is defined for your disease of interest, SBI can help answer the question:
  • Is this a druggable target?
      • Does it have sequence/domains similar to known targets?
      • Does the target have a site where a drug can bind, and with appropriate affinity?

13. Genome Annotation and Analysis 14. Impact of Structural Bioinformaticson Drug Discovery .Speeds up key steps in DD process by combining aspects of bioinformatics, structural biology, and structure-based drug design 15. human genome polysaccharides lipids nucleic acids proteins Problems with toxicity, specificity, and difficulty in creating potent inhibitors eliminate the first 3 categories... 16. druggable genome= subset of genes which express proteins capable of binding small drug-like molecules human genome polysaccharides lipids nucleic acids proteins proteins with binding site 17. Proteomics

  • Proteomics studies networks of proteins by measuring, among other things, protein expression.
  • Protein activity is regulated by post-translational modification and degradation; these cannot yet be predicted from DNA sequence.
  • Proteomics measures protein expression directly, not via gene expression, thus achieving better accuracy. Current work uses 2-dimensional polyacrylamide gel electrophoresis (2D-PAGE) and mass spectrometry.
  • New separation and characterization technologies, such as protein microarrays and high-throughput chromatography, are being developed

18. Proteomics 19. Process Flow Chart of Proteomics (Image) analysis (Data massage, Evaluation) Spot identification (Mass spectrometry) Biomarkers (Principal compound analysis) Two dimensional gel electrophoresis 20. Proteomics in Drug Discovery

  • As we have seen genomics has dramatically altered the way drug discovery is now being viewed.
  • However, there may not be a good correlation between gene expression and protein expression as most disease processes and treatments are manifest at the protein level.
  • It is believed that gene-based expression analysis alone will be totally inadequate for drug discovery.

21. Proteomics is Drug Discovery

  • Proteomics has unique and significant advantages as an important complement to a genomics approach.
  • Target/marker identification
  • Target validation/toxicology

22. Target/marker identification

  • This application of proteomics provides a protein profile of a cell, tissue and/or bodily fluids that can be used to compare a healthy with a diseased state for protein differences in the search for drugs or drug targets.

23. Target validation/toxicology

  • Proteomics can be applied as an assay procedure for the potential utility of drug candidates.
  • This can be achieved by a comparative analysis of reference protein profiles from normal or diseased states with profiles after drug treatment (Wang 1999).
  • Proteomics technology can also be integrated with combinatorial chemistry to evaluate comparative structure-activity relationships of drug analogs.

24. Protein-Ligand Docking Starting orientation of the program with 2 water molecules as the Protein and Ligand (a useful setup for testing the application). The energy of the system is in J/mol. 25. Protein-Ligand Docking Independent control of both molecules is allowed. The leftmost molecule is rotated using a trackball style rotation, while the second molecule remains fixed. 26. Protein-Ligand Docking From the previous figure, the second molecule has been independently translated up and away from the first molecule. Molecules can be arbitrarily positioned and oriented in 3D 27. Protein-Ligand Docking This is the same setup as the previous figure, except the viewpoint has been rotated, translated and zoomed to a different location. The energy of the system remains the same as the molecules are physically unmoved relative to each other 28. Protein-Ligand Docking The two oxygen atoms are just overlapping and consequently the energy of the system takes on a large negative value indicating a VERY high energy (the energy well is reversed for the purpose of the program, so large positive values indicate a favourable conformation, and large negative values indicate unfavourable conformations 29. Protein-Ligand Docking Here the atoms are at an optimum distance for the van der Waals Forces to hit the minimum of the well potential. However, the atoms are not aligned for any dipole-dipole interaction or hydrogen bonding 30. Protein-Ligand Docking The energy of the system attains a maximum with the following orientation. This is the orientation that occurs between water molecules when ice forms. This puts the hydrogen bond in its optimum orientation, and this changes makes another order of magnitude difference in the energy of the system 31.

  • Structure being the key to function, determining a proteins structure is a key step toward elucidating its role.
  • The subfield of protein-ligand docking is useful in rational drug design.
  • Laboratory prediction is time consuming and expensive, so researchers have been working on computerized prediction for several decades.
  • Exact computational prediction is difficult but sophisticated algorithms to find approximate solutions continue to be developed.

Protein-Ligand Docking 32. Critical Assessment of Methods of Protein Structure Prediction