Table 2.

Structural features

Feature	Description
Stem	Number of stems
Overhang	Number of overhangs
Stem_max	Length of the maximal stem in the target sequence
Loop_mismatch	Number of loops that only contain two mismatch bases
Loop_symm	Number of symmetric loops that contain more than two bases
Loop_asym	Number of asymmetric loops that contain more than two bases
Stemsa	8 features, number of stems of length 6-0 and those with length < 6 and > 10
Loopsb	8 features, the number of loops with length of 1-7 and those with length > 7
Bulgesc	8 features, number of bulges with length of 1-7 and those with length > 7

^a A stem is defined as a set of consecutive pairs separated by unpaired bases.

^b A loop is defined as a set of unpaired bases between two strands.

^c A bulge is defined as a set of unpaired bases only in one strand