The O2-scavenging flavodiiron protein in the human parasite Giardia intestinalis.

The flavodiiron proteins (FDP) are widespread among strict or facultative anaerobic prokaryotes, where they are involved in the response to nitrosative and/or oxidative stress. Unexpectedly, FDPs were fairly recently identified in a restricted group of microaerobic protozoa, including Giardia intestinalis, the causative agent of the human infectious disease giardiasis. The FDP from Giardia was expressed, purified, and extensively characterized by x-ray crystallography, stopped-flow spectroscopy, respirometry, and NO amperometry.

Neuroglobin, nitric oxide, and oxygen: functional pathways and conformational changes.

Neuroglobin (Ngb) is a globin expressed in the nervous system of humans and other organisms that is involved in the protection of the brain from ischemic damage. Despite considerable interest, however, the in vivo function of Ngb is still a conundrum. In this paper we report a number of kinetic experiments with O2 and NO that we have interpreted on the basis of the 3D structure of Ngb, now available for human and murine metNgb and murine NgbCO.

Proton uptake upon anaerobic reduction of the Paracoccus denitrificans cytochrome c oxidase: a kinetic investigation of the K354M and D124N mutants.

The kinetics and stoichiometry of the redox-linked protonation of the soluble Paracoccus denitrificans cytochrome c oxidase were investigated at pH = 7.2-7.5 by multiwavelength stopped-flow spectroscopy, using the pH indicator phenol red.

Cytochrome bo(3) from Escherichia coli: the binding and turnover of nitric oxide.

The reaction of nitric oxide (NO) with fast and reduced cytochrome bo(3)(cyt bo(3)) from Escherichia coli has been investigated. The stoichiometry of NO binding to cyt bo(3) was determined using an NO electrode in the [NO] range 1-14 microM. Under reducing conditions, the initial decrease in [NO] following the addition of cyt bo(3) corresponded to binding of 1 NO molecule per cyt bo(3) functional unit.