METAL TRANSPORT, GENE REGULATION, VIBRIO CHOLERAE, TRANSCRIPTION REGULATION, ZINC, IRON, REPRESSOR, CYTOPLASM, DNA-BINDING, TRANSCRIPTION, METAL-BINDING, FERRIC UPTAKE CRYSTAL STRUCTURE OF THE VIBRIO CHOLERAE FERRIC UPTAKE REGULATOR (FUR) REVEALS STRUCTURAL REARRANGEMENT OF THE DNA-BINDING DOMAINS 2W57