Incision of the 50-bp substrate containing a cholesterol lesion (G1). The substrate was incubated with UvrA, UvrB, and wtUvrC (lane 1) or UvrC(D399A) (lane 2), or Cho (lane 3). A DNase I ladder of substrate G1 was used as a reference (lane 4). The sizes of the different incision products are indicated. Note that for proper determination of the size of the Cho incision product, much less radioactive substrate was put on the gel, and as a result the nonincised 50-mer in lane 3 is hardly visible.