Fig. 2.

(A) 3D rendition of the binding pocket for clin in the central loop of domain V of 23S rRNA (40). Clindamycin is shown in pink, the six nucleotides randomized for the selection are shown in blue (numbered 2057-2062), and the two positions where mutations were selected for in vitro are shown in darker blue. The figure was made in ribbons (49). The 2D structure of clin is shown at bottom right. (B) Cassette mutagenesis strategy. Details of the sequence changes made in pLK-45 to construct a DNA cassette to be removed by restriction digestion and replaced with one containing randomized sequence.