Figure 1.

Schematic representation of 1–570 RNA. (A) Primary structure, where mapping of band X is indicated relative to 1–570 RNA and previously published products of the RNase III reaction with RNA in the closed conformation (‘C’). (B) Proposed secondary structures. Left: closed (‘C’) conformation. Solid arrowheads indicate the RNase III cleavages in the LRA. Right: linear open (‘O’) conformation; new cleavage in stem-loop VI indicated with an arrow; (C) detailed sequences of the double helical elements recognized by RNase III.