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Find the best starting enzyme Find the hotspots Select the best mutations at these hotspots. Glucokinases. Hexokinases. Allowed amino acids at pos. 64 (46 in alignment) = A,G,P,S,C. Hexokinases. Allowed amino acids: A,G,P,S.
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Find the best starting enzyme • Find the hotspots • Select the best mutations at these hotspots
Glucokinases Hexokinases
Allowed amino acids at pos. 64 (46 in alignment) = A,G,P,S,C
Hexokinases Allowed amino acids: A,G,P,S Glucokinases
Can we change a hexokinase into a glucokinase? With a smart library (size 32) targeted at these correlating positions -> 10 fold increase of glycokinase activity.
WT = P27Y28 Y28G -> 10% Y28GP27A -> 200% control P27A -> 15%Y28GP27E -> 85% Y28GP27R -> 80% G28 -> P,A -> no act.
Y28DP27G -> 300% Y28RP27N -> 200% all others less active as wild type
Inhibitor Design The ICL-like superfamily: * OAH is a member * Used by fungi produce oxalate (toxic) The most conserved residues ( >97% ) Correlating positions
O O- Glu(100%) OAH: O- OH OH HO O- O- OH O- OH O- HO HO OH OH HO O- O- OH Inhibitor Design ICL:
Inhibitor Design OAH: Ser157 -> A, P or T : Km = 1200, 600, 800 x WT kcat = 0.2, 0.3, 0.4 X WT ICL: Pro157 -> S: Km = 50 x WT, kcat = equal to wildtype OAH: Ser157Pro: Changed specificity. Increased the affinity of OAH for a isocitrate like compound Petal death protein: Ser157Pro: Selectively removed OAH activity
Inhibitor Design OH OH O- F O- HO F O- OH OH O- OH 100% Diol
Subsets and data comparison Correlating different data types: Correlation between fungi that are known oxalic acid producers and the amino acids in the alignment. -> make subset Select all amino acids that are conserved within this group and a different residue in the rest of the alignment. The best scoring amino acid = S157!!!!!
Smart library design Always think!!!! • Enantioselectivity: • Select all mutations from articles that are known to have effect on enantioselectivity and plot these in the protein of interest. • Design library at these positions taking high # of positions with low # of different aa. • Thermostability: • Select positions that are flexible in the structure (B-FIT values/RMSD) excluding parts that move to perform the function • Introduce the most common residues at these positions • Selectivity: • Select mutations from articles that are known to have effect on specificity and/or use correlated mutation data.