FIGURE 7.

2′F B6 distinguishes between two highly similar proteins. A, plot of the loss of signal intensity of resonances in native hβ₂m upon binding to a 2-fold molar excess of 2′F B6min using data shown in Fig. 5A. Profiles were calculated as the ratio of the peak intensity in the presence (I) or absence (I^o) of a 2-fold molar excess of aptamer. Intensity profiles were normalized to residues 40–45 that are not involved in the interface. Residues with a ratio of <0.2 are colored red, those showing a ratio between 0.2 and 0.4 are colored yellow, and those with no significant decrease in intensity are colored gray. The structure of hβ₂m drawn as a surface representation is shown on the right color-coded using the same scale. Residues with no assignments (na) are shown in blue. B, as described in A, but for the interaction of 2′OH B6min and hβ₂m. C, as described in A, but for the interaction of 2′F Β6min with ΔΝ6. The secondary structure elements of the proteins are shown as ribbons on top of the panels.