27.12.2012 Views

l - People

l - People

l - People

SHOW MORE
SHOW LESS

You also want an ePaper? Increase the reach of your titles

YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.

The ROC curve is simply a plot of the true positive rate (same as sensitivity) vs. false<br />

positive rate (1-specificity), for each value of the threshold, as the threshold is varied<br />

from +1 to -1, a range which included all possible values of HingeMaster score, hNMa,<br />

and the squared-normalized displacement of the higher modes described in the discussion<br />

of hNMa. For a good predictor, the true positive rate will increase faster than the false<br />

positive rate as the threshold is lowered, and the area under the curve will be significantly<br />

greater than 0.5<br />

Holm and Sander-like correlation matrix partitioning (hNMe)<br />

As explained in the main text, Holm and Sander made a hinge predictor which analyzed<br />

contact matrices. The basic idea is that for domain hinge bending proteins, two or more<br />

submatrices lying on the diagonal correspond to continuous stretches of polypeptide<br />

within a structural domain. Correspondingly, each such submatrix contains many<br />

interconnected residues, represented by matrix elements set to “1”. If two such<br />

submatrices correspond to different structural domains then the elements of the complete<br />

matrix which connect the submatrices will be poor in contacts, and will largely be set to<br />

“0”. It is possible to partition the complete matrix into such submatrices by iteratively<br />

moving the boundaries of all possible submatrices, but in the most general case this<br />

would be prohibitively expensive.<br />

Holm and Sander instead extract the lowest-order nontrivial eigenvector of the contact<br />

matrix, then sort the residues according the value assigned to each residue by that<br />

198

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!