1,721,051 research outputs found
Rigidity of the heme pocket in the cooperative Scapharca hemoglobin homodimer and relation to the direct communication between hemes.
No full text
The truncated oxygen-avid hemoglobin from Bacillus subtilis: X-ray structure and ligand binding properties
No full textIron and proteins for iron storage and detoxification
No full textIron is required by most organisms, but is potentially toxic due to the low solubility of the stable oxidation state, Fe(III), and to the tendency to potentiate the production of reactive oxygen species, ROS. The reactivity of iron is counteracted by bacteria with the same strategies employed by the host, namely by sequestering the metal into ferritin, the ubiquitous iron storage protein. Ferritins are highly conserved, hollow spheres constructed from 24 subunits that are endowed with ferroxidase activity and can harbour up to 4500 iron atoms as oxy-hydroxide micelles. The release of the metal upon reduction can alter the microorganism-host iron balance and hence permit bacteria to overcome iron limitation. In bacteria, the relevance of the Dps (DNA-binding proteins from starved cells) family in iron storage-detoxification has been recognized recently. The seminal studies on the protein from Listeria innocua demonstrated that Dps proteins have ferritin-like activity and most importantly have the capacity to attenuate the production of ROS. This latter function allows bacterial pathogens that lack catalase, e.g. Porphyromonas gingivalis, to survive in an aerobic environment and resist to peroxide stress
ZnuA, the soluble component of the bacterial Zn(II) ABC transporter, a possible target for novel antibiotics
No full text
Effect of the vinyl-globin interactions on the temperature-dependent broadening of the Soret spectra: A study with horse myoglobin and Scapharca dimeric hemoglobin reconstituted with unnatural 2,4-heme derivatives
No full textThe temperature dependence of the Soret absorption spectra has been measured over the range 80 to 300 K on deoxygenated and carbonmonoxy horse heart myoglobin and Scapharca inaequivalvis dimeric hemoglobin reconstituted with proto- or with meso- and deutero-heme, in which the vinyl groups have been replaced with ethyl groups or hydrogen atoms, respectively, In the meso- and deutero-derivatives of both proteins the linewidth of the absorption spectra is narrower and less sensitive to thermal broadening effects than in the proto-derivatives. Moreover, the broadening effects are larger in the deoxygenated proteins with respect to the liganded adducts. The quantitative analysis of these effects shows that the change in linewidth is due to a marked decrease in the extent of coupling between the heme vibronic transitions and the protein low-frequency motions. The relevance of the vinyl groups in the dynamics of the heme-globin interaction is highlighted by this experimental approach which shows that the protein is capable of transmitting structural information to the heme by coupling the ensemble of the low-frequency modes to the stereochemistry of the vinyl itself. This mechanism, which entails adjustment of the equilibrium between vinyl torsional conformers, represents an additional pathway for the control of the heme reactivity in addition to the iron-histidine link. (C) 1997 Academic Press
UNUSUAL AFFINITY OF CYANIDE FOR FERROUS AND FERRIC SCAPHARCA INAEQUIVALVIS HOMODIMERIC HEMOGLOBIN. EQUILIBRIA AND KINETICS OF THE REACTION
No full textAn update on structural insights into the enzymes of the polyamine-trypanothione pathway: Targets for new drugs against leishmaniasis
No full textCrystallization and preliminary X-ray crystallographic analysis of the unusual ferritin from Listeria innocua
Full text linkSingle crystals of ferritin extracted from Listeria innocua have been obtained by the vapour-diffusion method using PEG 1000 as precipitant. The crystals are orthorhombic, space group P212121, with unit-cell dimensions a = 87.7, b = 137.5, c = 173.1 Å. The crystals diffract to 2.9 Å resolution on a rotating-anode X-ray source and to 2.35 Å resolution on a synchrotron X-ray source. The asymmetric unit contains one molecule formed by 12 subunits, corresponding to a packing density of 2.41 Å3 Da-1
- …
