Direct Observation of Transition-State Dynamics during Folding Reactions

Direct molecular dynamics observation of protein folding transition state ensemble.

The concept of the protein transition state ensemble (TSE), a collection of the conformations that have 50% probability to convert rapidly to the folded state and 50% chance to rapidly unfold, constitutes the basis of the modern interpretation of protein engineering experiments. It has been conjectured that conformations constituting the TSE in many proteins are the expanded and distorted forms...

Femtosecond real‐time probing of reactions. XXI. Direct observation of transition‐state dynamics and structure in charge‐transfer reactions

Direct observation of steady-state microtubule dynamics

Different types of unusual dynamic behavior have been reported for steady-state microtubules. While almost all earlier reports relied on kinetic measurements of bulk polymerization, we have directly visualized the steady-state addition of subunits to individual microtubules through the use of tubulin derivitized with biotin. Biotinylated tubulin was used both as an internal "seed" for polymeriz...

Direct observation of ultrafast folding and denatured state dynamics in single protein molecules.

Single-molecule fluorescence resonance energy transfer (smFRET) experiments are extremely useful in studying protein folding but are generally limited to time scales of greater than approximately 100 micros and distances greater than approximately 2 nm. We used single-molecule fluorescence quenching by photoinduced electron transfer, detecting short-range events, in combination with fluorescenc...

Molecular dynamics simulations of protein folding from the transition state.

Putative transition-state ensemble (TSE) conformations of src SH3 were identified by monitoring the deviation from the experimental phi values along molecular dynamics (MD) simulations of unfolding. Sixty MD trajectories (for a total of about 7 micros) were then started from the putative TSE. About one-half of the 60 runs reached the folded state while unfolding was observed in the remaining ha...