Sheffield Institute for Nucleic Acids

Dr Timothy Craggs

Research Interests

Single-molecule approaches provide unprecedented detail to the understanding of essential biological processes, as was recognized in the awarding of the 2014 Nobel Prize for Chemistry. Their unique advantage stems from the ability to go beyond the ensemble- and time-averaging of common biochemical techniques, enabling the identification and interpretation of asynchronous reactions, transient states, and rare sub-species.

ResTDCResearch in the Craggs Lab involves the development and application of single-molecule fluorescence techniques to addressing crucial questions across physics, chemistry and the life sciences. Recent work has focussed on the development and application of single-molecule fluorescence resonance energy transfer (smFRET – a molecular ruler for the 30-90 Å scale) to questions of protein folding, and DNA transcription, replication and repair. These methods are capable of observing individual molecules and molecular interactions in real time, and understanding their dynamics.

In addition to this mechanistic work, we have shown we can use smFRET to measure absolute distances with angstrom accuracy, opening the door to FRET driven structural biology.


  • Nott TJ, Craggs TD & Baldwin AJ (2016) Membraneless organelles can melt nucleic acid duplexes and act as biomolecular filters. Nature Chemistry, 8: 569-575.
  • Algasaier SI, Exell JC, Bennet IA, Thompson MJ, Gotham VJB, Shaw S, Craggs TD, Finger LD and Grasby JA. (2016) DNA and Protein Requirements for Substrate Conformational Changes Necessary for Human Flap Endonuclease-1 Catalyzed Reaction. Journal of Biological Chemistry, 291: 8258-8268
  • Evans GE, Hohlbein J, Craggs TD, Aigrain L and Kapanidis AN. (2015) Single-molecule FRET reveals real-time conformational changes in the fingers subdomain of DNA polymerase I.  Nucleic Acids Research, 43: 5998-6008
  • Nott TJ, Petsalaki E, Farber P, Jervis D, Fussner E, Plochowietz A, Craggs TD, Bazett-Jones D, Pawson T, Forman-Kay JD, Baldwin AJ. (2015) Phase Transition of a disordered Nuage Protein generates environmentally responsive membraneless organelles. Molecular Cell, 57: 936-947
  • Craggs TD, Hutton RD, Brenlla A, White MF, Penedo JC. (2014) Single-molecule characterization of Fen1 and Fen1/PCNA complexes acting on flap substrates. Nucleic Acids Research, 42: 1857-1872.
  • Hohlbein J, Craggs TD, Cordes T. (2014) Alternating-laser excitation: single-molecule FRET and beyond. Chemical Society Reviews, 43: 1156-1171.
  • Hohlbein J, Aigrain L, Craggs TD, Bermek O, Potapova O, Shoolizadeh P, Grindley NDF, Joyce CM, and Kapanidis AN. (2013) Conformational landscapes of DNA polymerase I and its mutator derivatives establish critical checkpoints for nucleotide insertion fidelity. Nature Communications 4: 2131.
  • Craggs TD and Kapanidis AN. (2012) Six steps closer to FRET-driven structural biology.  Nature Methods 9: 1157-1159.
  • Craggs TD. (2009) Green fluorescent protein: structure, folding and chromophore maturation.  Chemical Society Reviews, 38: 2865 (invited review)
  • Orte A, Craggs TD, White SS, Jackson SE and Klenerman D. (2008) Evidence of an intermediate and parallel pathways in protein unfolding from single-molecule fluorescence.  Journal of the American Chemistry Society, 130: 7898–7907.

Dr Timothy D. Craggs
Lecturer in Biological Chemistry
Department of Chemistry