FIG. 1.

(A) Physical map of the region surrounding the circularin A structural gene cirA of C. beijerinckii ATCC 25752. Solid arrows indicate genes; bent arrows show putative promoters; lollipops represent predicted regions of dyad symmetry (ΔG⁰ < −10 kcal/mol); dotted arrows show possible polycistronic messengers. Map units are base pairs. (B) Schematic representation of the cir DNA fragments in the indicated plasmids and locations of the deletions (indicated by the thin lines). Open arrowheads indicate a deletion in cirE. Promoters are shown by bent arrows. CirA⁺, circularin A production; Cir^R, circularin A resistance, denoted as ++, full protection against CirA [>24-fold increase relative to E. faecalis JH2-2(pMG36c)]; +, partial protection [2- to 16-fold increase relative to E. faecalis JH2-2(pMG36c)]; −, sensitive.