Abstract
Precise measurement of the potential of mean force is necessary for a fundamental understanding of the dynamics and chemical reactivity of a biological macromolecule. The unique advantage provided by the recently developed constant-information approach to analyzing time-dependent single-molecule fluorescence measurements was used with maximum entropy deconvolution to create a procedure for the accurate determination of molecular conformational distributions, and analytical expressions for the errors in these distributions were derived. This new method was applied to a derivatized poly(L-proline) series, P nCG 3K-(biotin) (n = 8, 12, 15, 18, and 24), using a modular, server-based single-molecule spectrometer that is capable of registering photon arrival times with a continuous-wave excitation source. To account for potential influence from the microscopic environment, factors that were calibrated and corrected molecule by molecule include background, cross-talk, and detection efficiency. For each single poly(L-proline) molecule, sharply peaked Förster type resonance energy transfer (FRET) efficiency and distance distributions were recovered, indicating a static end-to-end distance on the time scale of measurement. The experimental distances were compared with models of varying rigidity. The results suggest that the 23 A persistence length wormlike chain model derived from experiments with high molecular weight poly(L-proline) is applicable to short chains as well.
Original language | English (US) |
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Pages (from-to) | 5191-5203 |
Number of pages | 13 |
Journal | Journal of Physical Chemistry A |
Volume | 110 |
Issue number | 15 |
DOIs | |
State | Published - Apr 20 2006 |
Externally published | Yes |
All Science Journal Classification (ASJC) codes
- Physical and Theoretical Chemistry