Redesigning protein pK_avalues

Abstract

The ability to re-engineer enzymatic pH-activity profiles is of importance for industrial applications of enzymes. We theoretically explore the feasibility of re-engineering enzymatic pH-activity profiles by changing active site pK a values using point mutations. We calculate the maximum achievable DpK a values for 141 target titratable groups in seven enzymes by introducing conservative net-charge altering point mutations. We examine the importance of the number of mutations introduced, their distance from the target titratable group, and the characteristics of the target group itself. The results show that multiple mutations at 10Å can change pK a values up to two units, but that the introduction of a requirement to keep other pK a values constant reduces the magnitude of the achievable DpK a . The algorithm presented shows a good correlation with existing experimental data and is available for download and via a web server at http://enzyme.ucd.ie/pKD.

Electrostatics in Proteins and Protein–Ligand Complexes

“…When reflects only the effect of electronic polarizability, values around 2 are used. When the reorganization of charges together with electronic polarizability is represented implicitly in the PBE model, the optimal value of can increase sometimes to values more than 20 [35,36].…”

Solvent reaction field potential inside an uncharged globular protein: A bridge between implicit and explicit solvent models?

“…The polar nature of water molecules influences the structure of proteins, nucleic acids, and lipid membranes. The processes that shape such structures are in turn related to the solubilities of (biologically relevant) ions [8] and the propensity of acidic or basic biochemical groups to ionize in solution [9][10][11][12][13][14][15][16][17][18].…”

Gene cloning, expression, and biochemical characterization of an alkali-tolerant β-mannanase from Humicola insolens Y1

“…It has been reported that the pH dependence of protein stability and enzymatic activity is often determined by the pKa values of active-site residues [19,31]. When enzymes perform at high pH values, their acid/base residues have to maintain higher pKa values [12].…”