Patent ID: 8981067
Filing Date: 2015-03-17
Classification: C07K,C12N,C12Y

Abstract:
1. A composition, comprising: a variant host cell derived from a parent host cell, the parent host cell characterized by a genome encoding a plurality of essential host proteins containing a plurality of histidines or basic amino acids residues such that when the cell is lysed, the essential proteins are capable of binding to a metal chelating matrix; wherein the variant host cell that is viable and differs from the parent host cell in that in the variant host cell: (a) at least one of the plurality of essential host proteins is additionally fused to an affinity binding tag encoded by the genome, the fusion proteins being capable of binding to a non-metal affinity matrix; or (b) at least one of the plurality of essential host proteins is mutated such that at least two of the plurality of histidines or basic amino acid residues are replaced with non-histidine residues so that the mutated essential protein is no longer able to bind the metal chelating matrix; the variant host cell being capable of being transformed to express a recombinant target protein.