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Fig. 1. Procedure for introducing mutations into the VSG 117 C-terminal GPI signal
sequence. In the first PCR reaction, the mutation was introduced into VSG 117
with the wild-type and mutant primers P1 and P2. The second PCR reaction used
the first PCR product (template 2) and a BspM I fragment (template 3)
as templates. The forward primer in this reaction was P1 and the reverse
primer P3. Because the final PCR product is a mixture of unmutated and mutated
sequence, several plasmids were subjected to sequencing to identify the
desired mutant derivative.