(
A) Graphic representation of capped RNAs containing hyperstabilized 5' SS but with variable BS/ΨBS used in these experiments and their corresponding label number. RNA sequences are given in
Supplementary file 1. (
B, C) Bar graph comparison of the fit parameters (τ
2, panel B, and the τ
2 amplitude A
2, panel C) obtained from analysis of Yhc1-L13F U1 lifetimes on RNAs 4 and 8 in the presence or absence of CA. On hyperstabilized 5' SS, presence of the BS suppresses switching to the long-lived Yhc1-L13F U1 complex (decreases A
2; compare A
2 for RNA 4 + CA vs. RNA 8 + CA). CA has a much smaller effect on A
2 (compare A
2 for RNA 8 ± CA) but still increases τ
2. However, suppression of both A
2 and τ
2 requires influences from both the 5' cap and BS. Details of the fit parameters for data shown in (
B, C) can be found in
Supplementary file 2, and bars in (
B, C) represent the fit parameters ± S.D.