Table 2

Proposed role of each mutation introduced into 8g8

8g8 mutationsGenerationMutation groupDistance to S189 OγProposed role for 8g8 mutations
160V1217.0  ÅStabilizes 64–74 and 414–420 loops. Allows 10 intramolecular H bonds.
L144M1117.8  ÅStabilizes 265–275 loop. Interacts with M358V, H322Y, and L343.
M358V1111.9  ÅShifts 265-275 and 315-324 loops (smaller shift than 56c8). Interacts with H322Y, L144M, and A343V.
Y370F1316.5  ÅPerhaps results in more favorable solvation.
A343V2125.0  ÅAlters packing among helices 9, 10, 11, and 15.
1437T3321.7  ÅForms intramolecular H bond, stabilizing helix 17.
H322Y4120.8  ÅPositions 315–324 loop. Determines the interaction between 265-275 active site loop and 315-324 loop. Interacts with M358V, L144M, and A343V.
L313F5310.7  ÅForms face-to-edge interaction with F314.
G412E5217.0  ÅPrecedes 413–421 loop, which is unstructured in WT. Forms salt bridge with R415.
T73K7221.1  ÅIn 65–75 loop, which is unstructured in WT. Forms salt bridge with E74.
T459S7428.4  ÅThr and Ser both H bond to H456. Small cost of exposing a methyl group is saved.
A56V8425.8  ÅNo observable changes.
A400T837.8  ÅThr-400 is in the active site.