Protein Conformation, Spectrophotometry, Ultraviolet, chemistry, Bacterial Proteins, Mutation, Escherichia coli, Binding Sites, Protein Binding, Glucose, Hydrogen-Ion Concentration, Spectrometry, Fluorescence, Models, Chemical, Tryptophan, Galactose, Chemical Phenomena, Glycosides, Methyl Ethers, Potassium Iodide