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esidues were differentially represented in hinges. In the course of the above, we
observed that one of the overrepresented residues (serine) is potentially catalytic; this was
the original motivation for question 4 above. To answer that question, we searched the
Catalytic Sites Atlas (CSA)[21] for close homologs to the proteins in our dataset, and
extracted the active site residue numbers from those proteins for comparison to the Hinge
Atlas annotation.
Our next task was to investigate hinge coincidence with secondary structure. Hinges are
generally believed to occur in disordered regions, but this belief has never been tested or
quantified rigorously to our knowledge.
Following up on our finding that hinges coincide with active site residues, we went on to
the question, are hinge residues more likely to be conserved than other residues, as active
sites are? We ranked the residues by relative conservation and examined the differences
between hinge and non-hinge residues.
Significant correlations between sequence features and hinges were found in the above
analyses. We computed Hinge Indices for each of these which may be used to relate
sequence features to flexibility. We then sought to determine what predictive value
sequence might have on its own and whether various sequence features collectively could
be used for prediction.
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