My research is focused on pushing the limits of single-molecule detection methods to study complex biological systems. His group develops state-of-the-art biophysical techniques (e.g., multicolor fluorescence, super-resolution imaging, combined force and fluorescence spectroscopy, vesicular encapsulation, single-molecule pull-down) and applies them to study diverse protein–nucleic acid and protein-protein complexes, and mechanical perturbation and response of these systems both in vitro and in vivo.

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Figure: Reaction in a nonocontainer.  Solution exchange allows controlled catalysis of protein-DNA interaction inside porous vesicles.  The pores in a nanocontainer let small molecules, such as ions and other chemicals, pass through but keep large molecules, such as proteins and DNA, inside.

Illustration courtesy of Ibrahim Cisse and Taekjip Ha.  Modified from Cisse I, Okumus B, Joo C and Ha T. 2007 Proceedings of the National Academy of Sciences USA 104: 12646.12650.

nano yoyo

Farhan’s paper on a “nano yoyo” for  low tension gauge tethers to define single molecular forces required for Notch activation is published in Nano Letters.

Real-time observation of Cas9

Digvijay Singh’s preprint on “Real-time observation of DNA recognition and rejection by the RNA-guided endonuclease Cas9” published in collaboration with Jennifer Doudna’s lab is published on BioRxiv.

Chemical Control of SNARE-Driven Membrane Fusion

Dae-Hyuk Kweon and Paul Heo’s work entitled “A Chemical Controller of SNARE-Driven Membrane Fusion That Primes Vesicles for Ca2+-Triggered Millisecond Exocytosis” is published in JACS.

Direct evidence for sequence-dependent attraction between double-stranded DNA controlled by methylation

Congratulations to Jejoong Yoo and Hajin Kim on their Nature Comm paper sequence-dependent attraction between dsDNA! This work is a collaborative effort with U. Illinois CPLC collabrator Alek Aksimentiev. Dr. Yoo used the Blue Waters Supercomputer at the National Center for Supercomputing Applications […]