Dear Francisco,
Dear All
I got recently a comment on a paper review suggesting me to perform CD
spectroscopy to determine the alpha-helical content of a mutant
protein involved in a human disease. The diferences between the wild
type and the mutant protein are just 17 aminoacids. My question is if
CD spectroscopy could detect secondary structure differences between
the wild-type and the mutant proteins based on this aminoacid
difference. Let's say, is it possible to detect by CD the presence or
absence of a 17 aa helix in a protein of 400 aa.
The answer is definitely yes. 17 out of 400 is ca. 4-5%. But your helix
content in the 400 residues will not be 100%. If it is mainly
alpha-helical, it will be ca. 50%. Then we are talking about 17 out of
200 residues, what is 8%.
I think the more important reason to analyze your deletion mutant by
CD is whether the residual fold stays intact after removal of one helix.
HTH
Guenter
I would appreciate your opinion
All the best
Francisco J. Enguita
ITQB
Oeiras
Portugal
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PD Dr. Guenter Fritz
Fachbereich Biologie
Sektion Naturwissenschaften
Universitaet Konstanz
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