TY - JOUR
T1 - Complex kinetics of the electron transfer between the photoactive redox label TUPS and the heme of cytochrome c
AU - Tenger, Katalin
AU - Khoroshyy, Petro
AU - Leitgeb, Balázs
AU - Rákhely, Gábor
AU - Borovok, Natalia
AU - Kotlyar, Alexander
AU - Dolgikh, Dmitry A.
AU - Zimányi, László
PY - 2005
Y1 - 2005
N2 - The photoinduced covalent redox label 8-thiouredopyrene-1,3,6-trisulfonate (TUPS) has been attached to two lysine residues (K8 and K39) at opposite sides of horse heart cytochrome c, as well as to cysteines, at the same positions, introduced by site-directed mutagenesis. Electron transfer between TUPS and the heme of cytochrome c deviates from the expected monoexponential kinetic behavior. Neither the overall rate nor the individual exponential components of electron transfer, as followed by kinetic absorption spectroscopy, correlate with the length of the covalent link connecting the dye with the protein. Molecular dynamics calculations show that TUPS can approach the protein surface and occupy several such positions. This heterogeneity may explain the multiexponential electron-transfer kinetics. The calculated optimal electron-transfer pathways do not follow the covalent link but involve through space jumps from the dye to the protein moiety, effectively decoupling the length of the covalent link and the electron-transfer rates.
AB - The photoinduced covalent redox label 8-thiouredopyrene-1,3,6-trisulfonate (TUPS) has been attached to two lysine residues (K8 and K39) at opposite sides of horse heart cytochrome c, as well as to cysteines, at the same positions, introduced by site-directed mutagenesis. Electron transfer between TUPS and the heme of cytochrome c deviates from the expected monoexponential kinetic behavior. Neither the overall rate nor the individual exponential components of electron transfer, as followed by kinetic absorption spectroscopy, correlate with the length of the covalent link connecting the dye with the protein. Molecular dynamics calculations show that TUPS can approach the protein surface and occupy several such positions. This heterogeneity may explain the multiexponential electron-transfer kinetics. The calculated optimal electron-transfer pathways do not follow the covalent link but involve through space jumps from the dye to the protein moiety, effectively decoupling the length of the covalent link and the electron-transfer rates.
UR - http://www.scopus.com/inward/record.url?scp=28944451319&partnerID=8YFLogxK
U2 - 10.1021/ci050181u
DO - 10.1021/ci050181u
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C2 - 16309248
AN - SCOPUS:28944451319
SN - 1549-9596
VL - 45
SP - 1520
EP - 1526
JO - Journal of Chemical Information and Modeling
JF - Journal of Chemical Information and Modeling
IS - 6
ER -