Electronic measurements of single-molecule catalysis by cAMP-dependent protein kinase A.

ABSTRACT: Single-molecule studies of enzymes open a window into their dynamics and kinetics. A single molecule of the catalytic domain of cAMP-dependent protein kinase A (PKA) was attached to a single-walled carbon nanotube device for long-duration monitoring. The electronic recording clearly resolves substrate binding, ATP binding, and cooperative formation of PKA's catalytically functional, ternary complex. Using recordings of a single PKA molecule extending over 10 min and tens of thousands of binding events, we determine the full transition probability matrix and conversion rates governing formation of the apo, intermediate, and closed enzyme configurations. We also observe kinetic rates varying over 2 orders of magnitude from one second to another. Anti-correlation of the on and off rates for P

SUBMITTER: Sims PC 

PROVIDER: S-EPMC3738266 | biostudies-literature | 2013 May

REPOSITORIES: biostudies-literature