Patent ID: 7930157

Claim:
A polypeptide synthesiser comprising a computer system for determining a rate of aggregation of a second polypeptide in relation to a reference polypeptide, wherein said reference polypeptide is defined by said reference polypeptide sequence, and wherein said second polypeptide amino acid sequence comprises a modified version of said reference polypeptide sequence, the computer system comprising: a data store for storing data comprising hydrophobicity data, β-sheet propensity data and charge data for a set of amino acids; a program store storing computer program code; and a processor, coupled to said program store and to said data store for implementing said stored code, and wherein said code further comprises code for controlling the processor to: input said second polypeptide amino acid sequence; determine a relative rate of aggregation for said second polypeptide by reading hydrophobicity data for said second polypeptide ammo acid sequence from said data store and determine a hydrophobicity value for said second polypeptide; reading charge data for said second polypeptide amino acid sequence from said data store and determine a β-sheet propensity value for said second polypeptide; determining an α-helix propensity value for said second polypeptide; obtaining hydrophobicity data, charge data, β-sheet propensity data and an α-helix propensity value for said reference polypeptide; and determining said relative rate of aggregation using said hydrophobicity, change, β-sheet and α-helix propensity data for said second and reference polypeptides by calculating [x*ΔHydr]+[y*(ΔΔG coil-α +ΔΔG β-coil )]−[z*ΔCharge], wherein x, y and z are scaling factors, (ΔHydr) is a difference in hydrophobicity between the reference polypeptide and the second polypeptide, (ΔΔG coil-α +ΔΔG β-coil ) is a difference in β-sheet propensity between the reference polypeptide and the second polypeptide and (ΔCharge) a difference in charge between the reference polypeptide and the second polypeptide, and select said second polypeptide for synthesis dependent upon the results of said relative aggregation rate determining.