FIG. 4.

Aligned restriction maps of selected plasmids of types A and B. Positions of individual xyl genes are depicted as in Fig. 3. Abbreviations: H, HpaI; S, SpeI; X, XbaI. Asterisks depict HpaI restriction sites absent from the catabolic gene area of pSVS23. Underlined are HpaI and SpeI restriction sites absent from the upper pathway operons in pSVS16 and pWW53. Filled circles mark SpeI sites absent from pSVS13, pSVS22, and pSVS23. The black bar indicates the region of pSVS13 used for probing plasmid backbone similarities. Doubly shaded bars indicate DNA areas in other plasmids hybridizing to the backbone probe. A putative 16-kb DNA insertion in pSVS16 (compared to pWW53) is shown as a broken line. Note the size and restriction site variability in the regions outside the catabolic genes.