[BiO BB] Ramachandran plot.
boris.steipe at utoronto.ca
Thu Mar 30 13:14:55 EST 2006
This is not misclassification: helices and strands have >>repeating<<
residues with certain (phi,psi) values. The Ramachandran plot shows
you a value for >>single<< residues. To classify a structural segment
as belonging to a certain type you need more information than
individual (phi,psi) values.
On 30 Mar 2006, at 10:57, Vivek Philip wrote:
> While analyzing the plot of phi and psi angles on the
> Ramachandran plot, we found out that there was a lot of overlap
> between the alpha-helix and beta-sheet regions. By this we mean
> that just based on the phi and psi angles alpha helices are meant
> to be both negative, while for beta sheets phi angles take negative
> values and psi positive. The results we used for generating these
> plots were obtained from STRIDE and DSSP for top 500 high
> resolution pdb structures.
> Does anyone have an idea as to what the reason for such an
> overlap could be? Moreover on further analysis we did see a lot of
> misclassification particularly related to the pi-helix region (Only
> about 38% of the residues were classified correctly).We are talking
> about approximately 40% overlap between the two regions.
> Any feedback on this would be greatly appreciated.
> Thank you,
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