| 摘要 |
The invention relates to biosensors, more particularly to protein biosensors and their use to indicate the formation of denaturing ice crystals in samples. The invention includes the use of a protein as a biosensor to indicate denaturing ice-crystal formation in a sample, wherein the protein is denaturable by denaturing ice crystals from a non-denatured state to a denatured state and wherein said non-denatured and denatured states are associated with detectably different indications, e.g. colour, fluorescence, bioluminescence, protein activity, etc. Biosensor compositions according to the invention preferably comprise a protein comprising a ligand-binding domain and a ligand bindable by the ligand-binding domain. Particularly good results are obtained using proteins, especially fluorescent proteins, having at least one polyhistidine tag and a ligand comprising imidazole or an equivalent polyhistidine-binding component. For example, polyhistidine-tagged Ds Red Express2 (Ds Red2) is especially preferred for use in the invention. On denaturation by denaturing ice crystals, this protein undergoes a marked change of colour indication from red to colourless. The invention is suitable for indicating the formation of denaturing ice crystals in a range of different samples susceptible to ice crystal damage, e.g. foodstuffs, pharmaceutical preparations, laboratory reagents, cells, tissues, etc. |
