PCSK9 crystal structure, PDB 2P4E. PCSK9 is the target in the published QSP applications discussed in this article. Latest QSP Using QSP to explain a dose-response plateau A mechanistic model can distinguish exposure limits from biological limits and guide the next measurement. Ramesh Sistla, PhD 3 min read
Medicinal chemistry A methyl group can change more than lipophilicity Interpreting methyl substitutions through conformational preference, local interactions, and measured properties. Kiran Bettadapur, PhD Target modalities Choosing a modality starts with the biology A practical comparison of inhibition, protein depletion, and suppression of protein synthesis. Ramesh Sistla, PhD PROTACs and molecular glues Designing productive complexes for PROTACs and molecular glues Productive protein recruitment depends on geometry, cellular context, and the steps after ternary-complex formation. Hemant Sistla Drug discovery overview Choosing a hit series that can survive the next experiment Hit confirmation and tractability should influence a program before a potency ranking becomes a chemistry plan. Ramesh Sistla, PhD Protein-ligand modeling Building a protein-ligand complex that can guide chemistry Preparation, pose selection, and experimental restraints determine whether a complex is useful for design. Shivanand K, PhD Target validation A knockout phenotype is only part of target validation Connecting human genetics, perturbation experiments, and chemical evidence before committing to a target. Ramesh Sistla, PhD AI/ML predictions Testing whether an ML model can predict the next chemistry round Validation should reflect the compounds, assays, and decisions the model will encounter after deployment. Saurabh Rana Physics based modeling Deciding which analogs deserve a free-energy calculation Relative binding free energies are most useful when the chemical question and simulation setup are well matched. Ramesh Sistla, PhD Physicochemical properties A solubility prediction needs a pH and a solid form Separating ionization, hydration, and crystal packing before choosing a chemical modification. Kuzhanthaivelan S, PhD Discovery trends Recent discovery methods face a prospective test Structure prediction and generative chemistry are changing project workflows; experimental follow-up determines their value. Ramesh Sistla, PhD Medicinal chemistry Growing a fragment without losing the reason it binds Weak binding can be a useful start when structural evidence and growth vectors support a tractable series. Kiran Bettadapur, PhD