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Sanaz Hossain

This was a graded course lab, not a published study. The design below is a proposed experiment, not one that was actually run — the docking results themselves are real output from an in-class exercise.

Molecular Docking

Modeling How a Drug Binds a Moving Target: Docking Tamiflu Against Shifting Flu Neuraminidase Strains

Coursework — computational lab (BCMB433)Spring 2024CourseworkAutoDock Vina, AutoDockTools, Monte Carlo simulation (Python)

What the system looked like before.

As I learned how to model 2D neighboring data points — in time, or along a chromosome — a course on analytical techniques in human disease began translating to me how a drug molecule physically interacts with a protein's binding pocket, based on atomic distances, energy states, and molecular constraints. Computation was a tool to simulate the fundamental biophysics of pharmacology — predicting exactly how a mutation in a virus might render a life-saving drug ineffective.

In plain terms: the course used molecular docking — computationally testing how well a small drug molecule fits into a protein's binding pocket — to study neuraminidase, an enzyme on the flu virus that lets new viral particles escape an infected cell. Drugs like Tamiflu (oseltamivir) work by jamming that pocket; different flu strains carry mutations there that can change how well the same drug binds.

Given a flu mutation (S247N) that resists two neuraminidase-inhibiting drugs but not a third, how would you design a docking study to confirm whether peramivir really does bind better — without that conclusion depending on how you set up the simulation?

To better uncover the mechanisms of peramivir binding to S247N, I would design an experiment that compared the binding of peramivir, oseltamivir, and zanamivir to S247N using three different box dimensions for each ligand — one small, sized to the proposed binding site based on active-site residue separation; one medium; one large. I'd use these to determine the binding affinity of each ligand, compare results at each volume between ligands to see if peramivir is truly a better binder, and compare the effect of varying volume for each ligand to determine what dimensions serve as a better basis for the theoretical binding site.

Monte Carlo hit-or-miss pi estimation output
Monte Carlo “hit-or-miss” π estimation — instructor-provided starter code, run with a personalized seed, not original code.

Including the paths that did not hold.

The guided lab

TriedAutoDock Vina docking simulations comparing oseltamivir (Tamiflu) and laninamivir (LVO) against two neuraminidase subtypes, N1 and N2, each from a real PDB crystal structure — a 40×40×40 Å search box for all runs, top-scoring poses ranked by predicted binding energy (kcal/mol, more negative = more stable).

On search-box size

TriedToo large a search box makes the result less precise and takes much longer, since there are more conformations to explore. Too small a box makes the result less accurate — more chance the true binding pocket gets cut out of the box, or the program's ability to explore conformations gets restricted. A smaller box does make the run faster, since there are fewer conformations to calculate.

In short

Top binding-affinity hits (kcal/mol, more negative = more stable): N1 + oseltamivir −6.756, N2 + oseltamivir −5.731, N1 + laninamivir −7.107, N2 + laninamivir −5.594..

Numbers first, not buried in prose.

Top binding-affinity hits (kcal/mol, more negative = more stable): N1 + oseltamivir −6.756, N2 + oseltamivir −5.731, N1 + laninamivir −7.107, N2 + laninamivir −5.594.

Based on the top affinity table, N1 is most affected by binding to oseltamivir; N2 is least affected — the more negative kcal/mol value for N1 indicates more free energy released on binding, a lower-energy, more stable state than the N2–oseltamivir complex. Laninamivir is the more effective ligand against N1 compared to oseltamivir, given its lower kcal/mol value. For N2, oseltamivir is the more effective ligand — it binds N2 with a slightly lower affinity than laninamivir does.

Where this went.

Coursework — not presented or published beyond the course.

Computation became a tool to simulate the fundamental biophysics of pharmacology, letting me model exactly how a mutation in a virus might render a drug ineffective — a topographical map, not unlike the ones in genomics lab, of how structural relationships at every scale determine a functional outcome.