Heme is a prosthetic group comprising ferrous iron (Fe(2+)) and protoporphyrin IX and is an essential cofactor in various biological processes such as oxygen transport (hemoglobin) and storage (myoglobin) and electron transfer (respiratory cytochromes) in addition to its role as a structural component of hemoproteins. Heme biosynthesis is induced during erythroid differentiation and is coordina...

Despite the mammalian host actively sequestering iron to limit pathogenicity, heme (or hemin when oxidized) and hemoproteins serve as important sources of iron for many bloodborne pathogens. The HmuRSTUV hemin uptake system allows Yersinia species to uptake and utilize hemin and hemoproteins as iron sources. HmuR is a TonB-dependent outer membrane receptor for hemin and hemoproteins. HmuTUV com...

Sodium fluoride induces changes in the heme dl components of both the frozen solution EPR and room temperature optical absorption spectra of oxidized Pseudomolurs cytochrome oxidase. The EPR resonances of the heme dl (iron-chlorin) moiety(ies) appear to undergo a rhombic to axial transition ( g = (2.52, 2.42, 1.73) 4 (2.54,2.54, 1.61)) with increasing concentrations of fluoride (0 3 0.1 M, pH ...

CONRAD, MARCEL E., LEWIS R. WEINTRAUB, DAVID A. SEARS, AND WILLIAM H. CROSBY. Absorption of hemoglobin iron. Am. J. Physiol. 2 I I (5) : I I 23-1 I 30. rg66.-Hemoglobin-iron was absorbed by the guinea pig as an iron-containing porphyrin compound. Absorption of both inorganic and hemoglobin-iron occurred primarily in the duodenum but about onethird of the quantity absorbed from the gut can be ab...

To further define the nature of abnormal iron deposits on the membranes of pathologic red blood cells, we have used sickle cell anemia (HbSS), HbSC, and beta-thalassemic erythrocytes (RBCs) to prepare inside-out membranes (IOM) and insoluble membrane aggregates (AGGs) containing coclustered hemichrome and band 3. Study of IOM from HbSC and thalassemic patients showed that amounts of heme iron a...

It is important to beginwith the distinctive properties of iron and its role as an essential micronutrient. Iron itself or as a component of heme and iron-sulfur clusters is required for numerous biological processes. Additionally, iron’s reactivity makes it quite toxic because it is able to catalyze Fenton reactions and generate dangerous hydroxyl radicals. Similarly, imbalances in the biogene...

We have used Mössbauer emission spectroscopy to study an oxygenated heme complex, produced in a frozen solution by nuclear decay from the isomorphous (57)Co-labeled compound. The Mössbauer parameters agree with those obtained by Mössbauer absorption spectroscopy of oxyhemoglobin. Thus, a nonprotein environment for iron can duplicate the unique oxyhemoglobin Mössbauer spectrum. The electronic st...

Iron is required as an element to sustain life in all eukaryotes and most bacteria. Although several bacterial iron acquisition strategies have been well explored, little is known about the intracellular trafficking pathways of iron and its entry into the systems for co-factor biogenesis. In this study, we investigated the iron-dependent process of heme maturation in Bacillus subtilis and prese...

Staphylococcus aureus is a human pathogen that represents a tremendous threat to global public health. An important aspect of S. aureus pathogenicity is the ability to acquire iron from its host during infection. In vertebrates, iron is sequestered predominantly within heme, the majority of which is bound by hemoglobin. To acquire iron, S. aureus binds hemoglobin, removes heme, and transports i...

Pseudomonas aeruginosa is a challenging pathogen due to both innate and acquired resistance to antibiotics. It is capable of causing a variety of infections, including chronic lung infection in cystic fibrosis (CF) patients. Given the importance of iron in bacterial physiology and pathogenicity, iron-uptake and metabolism have become attractive targets for the development of new antibacterial c...