l - People

!
h c
H < d c
D ,
h(
a)
then we reject 0 H iff our p-value ! HYP ( H,
D,
x,
d(
ai
)) < 0.05.
x=
"#
Results
Are certain amino acids more likely to occur in hinges?
We applied the described statistical formalism to the problem of amino acid frequency of
occurrence in hinges by taking C = amino acid type, and c to designate each of the 20
canonical amino acids. HI scores and p-values were thus calculated for each of 20
identifications of c corresponding to the 20 canonical amino acids.
Not surprisingly, we found that the small residues glycine and serine are overrepresented
in a highly significant fashion. We also found phenylalanine, valine, alanine, and leucine
to be underrepresented, albeit with lower significance (Figure 2.1, Table 2.1). We also
investigated the frequency of occurrence of sequential pairs of amino acids in hinges, but
since 400 sequential pairs are possible the significance of the results was much lower and
no conclusion could be drawn.
Are residues within a certain distance of an active site more likely to
be hinge residues?
64