Seminar by Dr Subrahmanyam Sappati

The Department of Physics is organising a guest seminar on Nuclear Quantum Effects and Photophysics of Low-Barrier Hydrogen Bonds: Implications for Drug and Material Design. The Speaker, Dr Subrahmanyam Sappati, Tenure Track Faculty at the Department of Pharmaceutical Technology and Biochemistry, Gdańsk University of Technology, Poland, will address the students.

About the Speaker:

Dr Subrahmanyam Sappati is an associate professor at the Department of Physical Chemistry at Gdańsk University of Technology. His scientific interests primarily lie in the areas of: Proton transfer mechanisms (Ground and excited state), /MM simulations in biological systems, Nuclear Quantum Effects and AIMD simulations. Dr Sappati is currently working with Prof. Raghunathan V. A, RRI Bangalore, on a project entitled “Fluid-fluid coexistence in phospholipid membranes induced by alcohols” in collaboration with Prof. Partha Hazra from IISER Pune.

Abstract:

Hydrogen bonds with unusually short donor–acceptor distances referred to as short-strong or low-barrier hydrogen bonds (SSHBs/LBHBs) exhibit highly non-classical behaviour that is strongly influenced by nuclear quantum effects (NQEs). These effects significantly modulate the structural dynamics, optical properties, and binding interactions of both biomolecules and molecular materials.

Through a series of first-principles and path-integral molecular dynamics (PIMD) simulations, we demonstrate how NQEs strengthen hydrogen bonds in asymmetric donor–acceptor environments, enhance proton delocalisation, and red-shift electronic absorption spectra, as observed in ellipticine–water complexes. In drug-target systems, such as the antitubercular drug. Bedaquiline binding to mycobacterial ATP synthase, SSHBs, contributes substantially to target specificity and binding free energy, a property tunable via chemical modifications. In molecular crystals, including glutamine derivatives and terephthalic acid, NQEs suppress classical proton transfer barriers, leading to bond symmetrisation and altered charge distributions.

Together, these findings underscore the critical role of NQEs and SSHBs in tailoring the photophysical and thermodynamic characteristics of complex molecular systems. Recognising and leveraging these effects provides new design principles for next-generation therapeutics and responsive materials.

Join the seminar and gain insights on Nuclear Quantum Effects and Photophysics of Low-Barrier Hydrogen Bonds: Implications for Drug and Material Design