Fig. 3.

Impact of albicidin binding on structure and stability of AlbAS. a Far-UV CD spectra of AlbAS in the absence (black) or presence (red) of albicidin (molar ratio 1.5:1 albicidin:AlbAS) at 21 °C. b–d CD-detected thermal unfolding of AlbAS in the absence (black) or presence (red) of albicidin, compound 5, or compound 7. T_m values are indicated by dashed lines. For the overlay, the [Θ]_{MRW(215 nm)} signals of AlbAS–albicidin and AlbAS–compound 5 were scaled to that of AlbAS alone using a factor of 1.157 and 1.091, respectively. e–g Overlay of ¹H-¹⁵N HSQC NMR spectra of AlbAS in the absence (black) or presence (red) of albicidin, compound 5, or compound 7, respectively. CD experiments were performed once. NMR experiments with the AlbAS–albicidin complex were performed five times and a representative spectrum is shown in e. NMR experiments using albicidin derivatives were conducted once