Quantitative structure-property relationships of azurin mutants from Pseudamonas aeruginosa

The method of partial least squares projections to latent structures (PLS) has been used to derive quantitative relationships between measured reduction potentials and structures of some Pseudomonas aeruginosa azurin mutants with changes in position 121. The models indicate that relatively few properties of the amino acids explain the experimental results obtained. Electronic characteristics exert a major influence on the models but also factors associated with acid-base strength, lipophilicity as well as with hydrogen bonding have large impact. The calculations also show that no single amino acid, natural or synthetic, can meet all of the optimum requirements of position 121 but indicate that a fine balance between various factors is a necessary prerequisite for a proper choice of residue to obtain a mutant with the desired properties.