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A study was conducted to investigate the iron release process from various forms of holo-ferric binding protein (FbpA), Fe(sub 3+)-FbpA-X, during the course of a chelator competition reaction using EDTA and Tiron. The results reaffirm the contribution of the synergistic anion to the FbpA iron transport process as the anion, in addition to playing a facilitative role in iron binding, and further establishes the synergistic anions as crucial players in periplasmic Fe(super 3+) transport in gram-negative bacteria.

Research was conducted to compare the effects of anions on oxygenation, oxidation and sulfhydryl reactivity of the heme iron in HbA0 and Hb Deer Lodge, beta-2(NA2)His->Arg. Results indicate that a large and substantial part of the shift in oxygen affinity caused by anion binding results from the increased conformational rigidity of the T state of deoxy Hb. Findings suggest that when deoxy Hb is present as the dominant species, significant greater changes in the initial stages of oxygenation than in oxidation curves occur as increases in anion levels occur.

The kinetics and mechanisms involved with loading of iron(III) into iron-free ferric binding protein A (FbpA) using iron(III) citrate as an iron source in the presence of excess citrate or phosphate (physiologically available anions) at pH 6.5 is reported. The findings demonstrated the important function of FbpA as a carrier for iron chelates as well as 'naked' or free iron acquisition processes of pathogenic Neisseria gonorrheae, Neisseria meningitidis, and Haemophilus influenzae.

The stability of unpurified proteins from rates of H/D exchange (SUPREX) is used for determining the identification and distribution of the synergistic anion in FeFbpA-X species in periplasmic preparations from Gram-negative bacteria. The studies have determined the identity of the in vivo anion bound to FeFbpA-X in the periplasm and has shown that the synergistic anion has played a structural and functional role in FbpA-mediated transport of iron across the periplasm and into the cytosol.

The mechanism of the ferric binding protein(FbpA)-mediated(sup 1) iron transport in pathogenic neisseria spp. and other gram-negative bacteria is investigated. Synergistic anion plays a critical role in the process of inserting Fe(sup 3+) into the Fbp binding site.

Iron-donating cycle of transferrin is examined. Findings suggest that iron complex with the transferrin receptor throughout the transferrin-to-cell cycle of iron uptake raise the reduction potential to more than 200mV.