Mutation in the Pro-Peptide Region of a Cysteine Protease Leads to Altered Activity and Specificity—A Structural and Biochemical Approach
Fig 5
X-ray structures of the mutants and WT (TS).
(a) Omit map (Fo-Fc) of I86L and I86F. The omit maps, contoured at 3.5σ level, were calculated by omitting the pro-peptide blocking the catalytic cleft. Catalytic domains of the two mutants are represented n electrostatic surfaces with the catalytic dyad in orange sphere superimposed therein. (b) Superposition of pro-peptide of I86L, I86F mutants and WT (TS). The propeptides are represented in ribbon. I86L, coloured in green; I86F, coloured in light blue; WT (TS) in light orange. The mature domain of the WT (TS) is in surface presentation with catalytic dyad in ball and stick. (c) Superposition of the mature catalytic domain with same color code used in (b). (d) and (e) The 2mFo-DFc electron density map at 1.5σ level of residues Tyr168, Tyr174 and Val220 in three proteins. The co-ordinates and structure factors of the WT (TS) have been taken from pdb_id 3TNX. ‘m’ and ‘p’ tags in the sequence number represent mature and pro-peptide region respectively.