Figure 1A. TOP I mutation corrrelated to CPT-11 resistance. NCBI reference sequence: NM_003286.1. (A) Protein sequence; Y, active catalytic tyrosine site; shaded location with underline: mutation site related to TOP I resistance; 1, region 1; 2-1 and 2-1, region 2; 3, region 3; 4, region 4 [see Redinbo et al (6) for the numbering of each region].
