Heme proteins green hemes

Lian T, Locke B, Kholodenko Y and Hochstrasser R M 1994 Energy flow from solute to solvent probed by femtosecond IR spectroscopy malachite green and heme protein solutions J. Rhys. 

Components forming the three-dimensional complex nitrophorin-1. A heme molecule (red) sits at the opening of a barrel-shaped protein (green and blue ribbons). A molecule of nitric oxide (blue- and red-ball figure) binds to an iron atom (black) in the heme. 

The green chromophore of MPO has received considerable attention because its visible absorption bands are red-shifted from those of most other heme proteins (39). Based on its spectroscopic properties, the chromophore has been identified as a high-spin ferric heme with formyl and vinyl porphyrin peripheral substituents, as in heme a of cytochrome... 

When free peroxidases or catalase react with hydroperoxides, stable green substances, called compounds I and II, are formed they have absorption spectra of yr-cation-radical type [Blumberg (7), Brill (16)]. This has been taken as evidence that stable Fem porphyrin cation radicals are formed by peroxide oxidation in these particular heme proteins [Borg (10), Dolphin (51)]. It is not known why the hydrogen peroxide does not attack the porphyrin ring, as is normal with hemoproteins, nor is it certain whether this radical formation has any biological implication. 

Stefano Bettati received his MS degree from the University of Parma in 1992, defending a thesis on The allosteric regulation of the enzyme tryptophan synthase, and his Ph.D. degree in 1998 from the University of Modena, by working on hemoglobin. He was a postdoctoral fellow at the laboratory of Chemical Physics, National Institutes of Health, Bethesda, MD, USA, from 1999 to 2000. At present he is a full professor at Applied Physics, Faculty of Medicine, University of Parma, Italy. His current research interests are mainly in structure, function, and dynamics relationships of PLP-dependent enzymes, heme proteins, and green fluorescent proteins. 

Myeloperoxidase contains two Fe heme-like centers, which give it the green color seen in pus. Hypochlorous acid is a powerful toxin that destroys bacteria within seconds through halogenation and oxidation reactions. It oxidizes many Fe and S-containing groups (e.g., sulfhydryl groups, iron-sulfur centers, ferredoxin, heme-proteins, methionine), oxidatively decarboxylates and deaminates proteins, and cleaves peptide bonds. Aerobic bacteria under attack rapidly lose membrane... 

LA. Andersson, T.M. Loehr, C.K. Chang, and A.G. Mauk, Resonance Raman spectroscopy of metallochlorins models for green heme protein prosthetic groups,/. Am. Chem. Soc. 107 182 (1985). 

Syntheses of porphyrins and metalloporphyrins have been widely investigated over the last three decades to provide models which mimic functions of heme proteins, heme enzymes and supramolecular assembly of chlorophyll in green plants and photosynthesis bacteria. Results on the syntheses and structure of biomimetic porphyrins up to 1985 have been reviewed by Morgan and Dolphin. ... 

R432 M. Nakamura, Nuclear Magnetic Resonance Studies on the Electronic Structure of Green Hemes and Green Heme Proteins , Global J. Inorg. Chem., [online computer file], 2012, 3, 1/1. 

Chlorocruorin a green respiratory protein containing heme(II) iron, found in the hemolymphs of some marine annelids. The C. of Spirographis (pi 4.3, M, 3 X10, twelve subunits of M, 250,000) has a heme component more closely related to the heme of cytochrome oxidase than to that of hemoglobin. 

The reversible one-electron oxidation-reduction of various heme proteins together with their similarity in spectra and magnetic susceptibilities establishes that the heme proteins normally occur in the ferrous and ferric states. However there is evidence that other states of oxidation may occur. For example, horse radish peroxidase is normally in the ferric state. Addition of HgOa forms intermediate (I), a green complex [Fe+++-peroxidase-HgOa] that has an absorption band at 657 m/i. Addition of one electron yields a red complex (II), which on addition of a second electron results in the appearance of the original ferric peroxidase. Is the red complex (II) [Fe+++-peroxidase-HO], or (Fe++++-peroxidase), or [Fe+++-peroxidase-... 

Fio. 23. Cooperation of various heme proteins in the oxidation of succinate with Oj in a muscle mitochondrion [tChance and Williams Green and Jarnefelt... 

In the mobile electron carrier cytochrome c, covalent bonds between cysteine (yellow) groups form between the heme (grey) portion and a protein (green) component. Oxygen atoms are shown in red. 

Figure 12.14 The three-dimensional structure of a photosynthetic reaction center of a purple bacterium was the first high-resolution structure to be obtained from a membrane-bound protein. The molecule contains four subunits L, M, H, and a cytochrome. Subunits L and M bind the photosynthetic pigments, and the cytochrome binds four heme groups. The L (yellow) and the M (red) subunits each have five transmembrane a helices A-E. The H subunit (green) has one such transmembrane helix, AH, and the cytochrome (blue) has none. Approximate membrane boundaries are shown. The photosynthetic pigments and the heme groups appear in black. (Adapted from L. Stryer, Biochemistry, 3rd ed. New York ...

FIGURE 22.18 Model of the R. viridis reaction center, (a, b) Two views of the ribbon diagram of the reaction center. Mand L subunits appear in purple and blue, respectively. Cytochrome subunit is brown H subunit is green. These proteins provide a scaffold upon which the prosthetic groups of the reaction center are situated for effective photosynthedc electron transfer. Panel (c) shows the spatial relationship between the various prosthetic groups (4 hemes, P870, 2 BChl, 2 BPheo, 2 quinones, and the Fe atom) in the same view as in (b), but with protein chains deleted. 

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