Purification and properties of the myo-inositol-binding protein from a Pseudomonas sp.

A myo-inositol-binding protein was isolated from a Pseudomonas sp. soil isolate and was purified to homogeneity. Its molecular weight is 30,000, and it has a single binding site. The amino acid analysis showed that the protein contains three tryptophan residues and no cysteine. Tryptophan residues seem to be involved in the binding of the ligand, as shown by the modification of the fluorescence spectra and by the fact that oxidation of tryptophan residues with N-bromosuccinimide abolished the binding of myo-inositol. Sequence analysis of the N-terminal segment of 37 amino acids showed that 13 are conserved when compared with the galactose-binding protein of Escherichia coli.