Professor Lubensky does theoretical and computational research at the interface between physics and biology. One recent focus of his work has been the rapidly growing area of systems biology. Rather than focusing on the properties of individual biological molecules, as biophysicists have traditionally done, this field seeks to understand how networks of interacting genes or proteins can collectively accomplish a particular biological function. For example, we know quite a bit about the receptors a bacterium uses to detect nutrients, the flagellar motors that drive its motion, and the signaling molecules that carry messages between them. But how do all of these components work together to allow it to reliably swim towards food? Professor Lubensky’s group addresses such questions by building mathematical models of particular biological systems. The qualitative behavior and robustness of these models are then analyzed with the goal of making novel, experimentally testable predictions. Systems of current interest include the developmental patterning of the fruit fly’s compound eye and circadian oscillations in cyanobacteria.

The second major area where Professor Lubensky is active is the physics of biopolymers. Here, he has paid particular attention to the properties of DNA and RNA, with an eye towards both basic physics and applications in biotechnology. In particular, Professor Lubensky is interested in how polymer dynamics is changed when molecules are strongly confined (as can happen, for example, in protein pores and in microfluidic devices) and in the relationship between nucleotide sequence and the mechanical stability of duplexes. He has also used basic results on the latter topic to study the dynamics of molecular motors such as helicases that use DNA as their track.

An allosteric model of circadian KaiC phosphorylation, (J.S. van Zon, D.K. Lubensky, P.R. Altena, and P.R. ten Wolde), PNAS 104, 7420 (2007).

Dynamics of Molecular Motors with Finite Processivity on Heterogeneous Tracks, (Y. Kafri, D.K. Lubensky, and D.R. Nelson), Phys. Rev. E 71, 041906 (2005).

Unzipping Kinetics of Double-Stranded DNA in a Nanopore, (A.F. Sauer-Budge, J.A. Nyamwanda, D.K. Lubensky, and D. Branton), Phys. Rev. Lett. 90, 238101 (2003).

Single Molecule Statistics and the Polynucleotide Unzipping Transition, (D.K. Lubensky and D.R. Nelson), Phys. Rev. E 65, 031917 (2002).