Fig. 2.

(A) A cartoon model of the ribbon structure of split GFP with fused PGB1 fragments. The model is produced using MOLMOL (42) and the pdb files 1ema (43) and 1pgb (44). (B) Topology of PGB1 fragments fused to GFP fragments. (C) Comparison of fluorescence intensity of Top1 and parent construct as well as negative (noninduced) and positive (CBD9k) controls. (D) The sequences of the fused fragments where the underlined part represents the PGB1 fragments. (E) Outline of the library with 3,456 possible sequences. Previously determined mutants that are stabilizing (F3, I7, I16, I18, E25, F29, I39), destabilizing (L18, Q25, K29), and possible mutations arising from the nature of the genetic code are included in the library. (F) Structure of parent protein where the seven library positions are indicated. The structures are produced using MOLMOL (41).