He-Wen Ma, Shaoqing Yang, Linda Yu and Chang-An Yu
Biochimica et Biophysica Acta (BBA) - Bioenergetics Volume 1777, Issue 3, March 2008, Pages 317-326
1 comment:
Anonymous
said...
This describes a very valuable mutant, and I mostly agree with the interpretation, but I have to argue with one conclusion: "This result (lack of stigmatellin-induced electron transfer from c1 to ISP when the disulfide is formed) confirms the observation that the elevation of ISP mid-point potential caused by stigmatellin binding is due to the fixation of ISP head domain at b position and not due to the binding of the inhibitor to ISP."
It is well known that stigmatellin does not bind to or raise the potential of soluble ISP. Furthermore from old work of Schagger, Brandt and coworkers, it does not bind to the bc1 complex in the absence of the ISP, or binds very weakly and in a different fashion. The binding site for stigmatellin involves the Qo pocket in cyt b and also the ISP, so by holding the ISP in the c1 position you prevent stigmatellin from binding. This leaves open the question whether the disulfide bond prevents stigmatellin-induced electron transfer by preventing the ISP from coming to the cyt b position or by preventing stigmatellin from binding.
1 comment:
This describes a very valuable mutant, and I mostly agree with the interpretation, but I have to argue with one conclusion:
"This result (lack of stigmatellin-induced electron transfer from c1 to ISP when the disulfide is formed) confirms the observation that the elevation of ISP mid-point potential caused by stigmatellin binding is due to the fixation of ISP head domain at b position and not due to the binding of the inhibitor to ISP."
It is well known that stigmatellin does not bind to or raise the potential of soluble ISP. Furthermore from old work of Schagger, Brandt and coworkers, it does not bind to the bc1 complex in the absence of the ISP, or binds very weakly and in a different fashion. The binding site for stigmatellin involves the Qo pocket in cyt b and also the ISP, so by holding the ISP in the c1 position you prevent stigmatellin from binding. This leaves open the question whether the disulfide bond prevents stigmatellin-induced electron transfer by preventing the ISP from coming to the cyt b position or by preventing stigmatellin from binding.
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