TABLE 2.

IRES activity of pseudoknot loop mutations

Sequence of mutation	% IRES activity (relative to wild type)a
AU AAAAA U (wild type [XLCSFV 1-442.NS′])	100
AU AAAAU U	113
AU AAAUU U	94
AU AAAUA U	92
AU AAUUU U	53
AU UUUAA U	52
AU UAAUA U	41
AU UUAAU U	37
AU UAUUA U	29
AU AUUUU U	28
AU UUUUU U	25
AU U (5-nt deletion)	6

^aIRES activity relative to the wild-type control was calculated as described in Table 1.