Figure 6.

Binding to α alters the conformation of UmuD. (A) Melting curves of 45 μM UmuD (solid line), 45 μM UmuD with 1 μM α (dotted line) and 45 μM UmuD′ (dashed line). The solid line shows the melting transitions for UmuD at 32°C and 60°C. The disappearance of the first melting transition suggests that the interaction between α and UmuD influences the conformation of the arms. (B) Percent UmuD-S60A cross-linked by using BMH in the presence of either full-length α, α1–280 or α917–1160. (C) Cartoon showing two possible conformations of the UmuD N-terminal arms. The star indicates the position of the C24 residues, which are cross-linked by BMH.