Block lab at Stanford University

A artist's impression of an RNA polymerase optical tweezers experiment

Research in our lab marries aspects of physics and biology to study the properties of proteins or nucleic acids at the level of single macromolecules and molecular complexes. Experimental tools include laser-based optical traps ("optical tweezers") and a variety of state-of-the-art fluorescence techniques, in conjunction with custom-built instrumentation for the nanometer-level detection of displacements and piconewton-level detection of forces. Current experimental work in our lab focuses on several biological motors and polymers, including RNA polymerase, riboswitches, and kinesin.

Click here for an introduction to optical tweezers.

Recent publications


  • Savinov, A., Block, S.M. Self-cleavage of the glmS ribozyme core is controlled by a fragile folding element. PNAS 115: 11976-11981. Full text
  • Milic, B., Chakraborty, A., Han, K., Bassik, M.C., Block, S.M. KIF15 nanomechanics and kinesin inhibitors, with implications for cancer chemotherapeutics. PNAS 115: E4613-E4622. Full text


  • Meng, C.A., Fazal, F.M., Block, S.M. Real-time observation of polymerase-promoter contact remodeling during transcription initiation. Nature Communications 8: 1178. Full text
  • Milic, B., Andreasson, J.O.L., Hogan, D.W., Block, S.M. Intraflagellar transport velocity is governed by the number of active KIF17 and KIF3AB motors and their motility properties under load. PNAS 114: E6830-E6838. Full text
  • Chakraborty, A., Meng, C.A., Block, S.M. Observing single RNA polymerase molecules down to base-pair resolution. Methods in Molecular Biology 1486: 391-409. Full text


  • Duesterberg, V.K., Fischer-Hwang, I.T., Perez, C.F., Hogan, D.W., Block, S.M. Observation of long-range tertiary interactions during ligand binding by the TPP riboswitch aptamer. eLife 12362. Full text
  • Fazal, F.M., Koslover, D.J., Luisi, B.F., Block, S.M. Direct observation of processive exoribonuclease motion using optical tweezers. PNAS 112: 15101-15106. Full text
  • Fazal, F.M., Meng, C.A., Murakami, K., Kornberg, R.D., Block, S.M. Real-time observation of the initiation of RNA polymerase II transcription. Nature 525: 274-277. Full text
  • Garcia-Garcia, C., Frieda, K.L., Feoktistova, K., Fraser, C.S., Block, S.M. Factor-dependent processivity in human eIF4A DEAD-box helicase. Science 348: 1486-1488. Full text
  • Andreasson, J.O.L., Milic, B., Chen, G.Y., Guydosh, N.R., Hancock, W.O., Block, S.M. Examining kinesin processivity within a general gating framework. eLife 07403. Full text
  • Andreasson, J.O.L., Shastry, S., Hancock, W.O., Block, S.M. The mechanochemical cycle of mammalian kinesin-2 KIF3A/B under load. Current Biology 25: 1166-1175. Full text


  • Blakely, B.L, Dumelin, C.E., Trappmann, B., McGregor, L.M., Choi, C.K., Anthony, P.C., Duesterberg, V.K., Baker, B.M., Block, S.M., Liu, D.R., Chen, C.S. A DNA-based molecular probe for optically reporting cellular traction forces. Nature Methods 11: 1229-1232. Full text
  • Milic, B., Andreasson, J.O.L., Hancock, W.O., Block, S.M. Kinesin processivity is gated by phosphate release. PNAS 111: 14136-14140. Full text