Observation of a power-law memory kernel for fluctuations within a single protein molecule.
The fluctuation of the distance between a fluorescein-tyrosine pair within a single protein complex was directly monitored in real time by photoinduced electron transfer and found to be a stationary, time-reversible, and non-Markovian Gaussian process. Within the generalized Langevin equation formalism, we experimentally determine the memory kernel K(t), which is proportional to the autocorrelation function of the random fluctuating force. K(t) is a power-law decay, t(-0.51 +/- 0.07) in a broad range of time scales (10(-3)-10 s). Such a long-time memory effect could have implications for protein functions.
Min
Wei
W
Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, USA.
Luo
Guobin
G
Cherayil
Binny J
BJ
Kou
S C
SC
Xie
X Sunney
XS
D000911:Antibodies, Monoclonal / Q000737:chemistry; D001710:Biotin / Q000737:chemistry; D019793:Fluorescein / Q000737:chemistry; D008954:Models, Biological; D008956:Models, Chemical; D011487:Protein Conformation; D011506:Proteins / Q000737:chemistry*; D019809:Streptavidin / Q000737:chemistry; D013816:Thermodynamics; D014443:Tyrosine / Q000737:chemistry*
D000911:Antibodies, Monoclonal; D011506:Proteins; D014443:Tyrosine; D001710:Biotin; D019809:Streptavidin; D019793:Fluorescein