Patent ID: 8865416

Claim:
An analyte sensor comprising an engineered fluorescent host polypeptide having a metal ion binding site comprising a plurality of negatively charged residues, wherein the negatively charged residues comprise a plurality of carboxyl oxygens orientated in a pentagonal bipyrimdal geometry wherein said geometry provides a metallic ion binding site operatively interacting with a chromophore region of the engineered fluorescent host polypeptide such that binding of a metal ion analyte to a molecular recognition motif modulates the emission of a fluorescent signal emitted by the fluorescent host polypeptide or the absorbance spectrum of the engineered fluorescent host polypeptide, and wherein the analyte sensor optionally includes a targeting motif for selectively targeting the endoplasmic reticulum of a cell, wherein the amino acid sequence of the analyte sensor is selected from the group consisting of SEQ ID Nos.: 104-105 and 121-141.