scholarly journals The Interaction of Covalently Bound Heme with the CytochromecMaturation Protein CcmE

2004 ◽  
Vol 279 (50) ◽  
pp. 51981-51988 ◽  
Author(s):  
Takeshi Uchida ◽  
Julie M. Stevens ◽  
Oliver Daltrop ◽  
Edgar M. Harvat ◽  
Lin Hong ◽  
...  
Keyword(s):  
Plant Mitochondria ◽  
Heme Iron ◽  
Histidine Residue ◽  
Axial Ligands ◽  
Heme Ligands ◽  
Essential Function ◽  
Resonance Raman Spectra ◽  
Vinyl Group ◽  
Covalently Bound

The heme chaperone CcmE is a novel protein that binds heme covalently via a histidine residue as part of its essential function in the process of cytochromecbiogenesis in many bacteria as well as plant mitochondria. In the continued absence of a structure of the holoform of CcmE, identification of the heme ligands is an important step in understanding the molecular function of this protein and the role of covalent heme binding to CcmE during the maturation ofc-type cytochromes. In this work, we present spectroscopic data that provide insight into the ligation of the heme iron in the soluble domain of CcmE fromEscherichia coli. Resonance Raman spectra demonstrated that one of the heme axial ligands is a histidine residue and that the other is likely to be Tyr134. In addition, the properties of the heme resonances of the holo-protein as compared with those of a form of CcmE with non-covalently bound heme provide evidence for the modification of one of the heme vinyl side chains by the protein, most likely the 2-vinyl group.

scholarly journals A heme-binding domain controls regulation of ATP-dependent potassium channels

2016 ◽  
Vol 113 (14) ◽  
pp. 3785-3790 ◽  
Author(s):  
Mark J. Burton ◽  
Sofia M. Kapetanaki ◽  
Tatyana Chernova ◽  
Andrew G. Jamieson ◽  
Pierre Dorlet ◽  
...  
Keyword(s):  
Metal Ion ◽  
Single Channel ◽  
Heme Iron ◽  
Receptor Subunit ◽  
Heme Binding ◽  
Prosthetic Group ◽  
Sulphonylurea Receptor ◽  
Spectroscopic Analyses ◽  
Heme Ligands

Heme iron has many and varied roles in biology. Most commonly it binds as a prosthetic group to proteins, and it has been widely supposed and amply demonstrated that subtle variations in the protein structure around the heme, including the heme ligands, are used to control the reactivity of the metal ion. However, the role of heme in biology now appears to also include a regulatory responsibility in the cell; this includes regulation of ion channel function. In this work, we show that cardiac KATP channels are regulated by heme. We identify a cytoplasmic heme-binding CXXHX16H motif on the sulphonylurea receptor subunit of the channel, and mutagenesis together with quantitative and spectroscopic analyses of heme-binding and single channel experiments identified Cys628 and His648 as important for heme binding. We discuss the wider implications of these findings and we use the information to present hypotheses for mechanisms of heme-dependent regulation across other ion channels.

Possible role of a histidine residue in the substrate specificity of yeast d-aspartate oxidase

2015 ◽  
pp. mvv108 ◽  
Author(s):  
Shouji Takahashi ◽  
Kozue Shimada ◽  
Shunsuke Nozawa ◽  
Masaru Goto ◽  
Katsumasa Abe ◽  
...  
Keyword(s):  
Substrate Specificity ◽  
Histidine Residue

scholarly journals Frequency dispersion reveals chromophore diversity and colour-tuning mechanism in parrot feathers

2018 ◽  
Vol 5 (7) ◽  
pp. 172010 ◽  
Author(s):  
Jonathan E. Barnsley ◽  
Elliot J. Tay ◽  
Keith C. Gordon ◽  
Daniel B. Thomas
Keyword(s):  
Frequency Dispersion ◽  
Animal Coloration ◽  
Molecular Conformations ◽  
Tuning Mechanism ◽  
Resonance Raman Spectra ◽  
Molecule Interactions ◽  
Yellow Region ◽  
Colour Tuning

Variation in animal coloration is often viewed as the result of chemically distinct pigments conferring different hues. The role of molecular environment on hue tends to be overlooked as analyses are mostly performed on free pigments extracted from the integument. Here we analysed psittacofulvin pigments within parrot feathers to explore whether the in situ organization of pigments may have an effect on hue. Resonance Raman spectra from a red region of a yellow-naped amazon Amazona auropalliata tail feather show frequency dispersion, a phenomenon that is related to the presence of a range of molecular conformations (and multiple chromophores) in the pigment, whereas spectra from a yellow region on the same feather do not show the same evidence for multiple chromophores. Our findings are consistent with non-isomeric psittacofulvin pigments behaving as a single chromophore in yellow feather barbs, which implies that psittacofulvins are dispersed into a structurally disordered mixture in yellow feathers compared with red feathers. Frequency dispersion in red barbs may instead indicate that pigments are structurally organized through molecule–molecule interactions. Major differences in the hues of parrot feathers are thus associated with differences in the organization of pigments within feathers.

The Role of Equatorial and Axial Ligands in Promoting the Activity of Non-Heme Oxidoiron(IV) Catalysts in Alkane Hydroxylation

2007 ◽  
Vol 2007 (19) ◽  
pp. 3023-3033 ◽  
Author(s):  
Leonardo Bernasconi ◽  
Manuel J. Louwerse ◽  
Evert Jan Baerends
Keyword(s):  
Axial Ligands ◽  
Alkane Hydroxylation

Isocitrate Lyase from Cephalosporium acremonium. Role of Mg2+ Ions, Kinetics, and Evidence for a Histidine Residue in the Active Site of the Enzyme

Biochemistry ◽  
1995 ◽  
Vol 34 (18) ◽  
pp. 6059-6068 ◽  
Author(s):  
Eusebio Perdiguero ◽  
Dolores de Arriaga ◽  
Felix Busto ◽  
Joaquin Soler
Keyword(s):  
Active Site ◽  
Isocitrate Lyase ◽  
Histidine Residue ◽  
Cephalosporium Acremonium

scholarly journals PARN-like Proteins Regulate Gene Expression in Land Plant Mitochondria by Modulating mRNA Polyadenylation

2021 ◽  
Vol 22 (19) ◽  
pp. 10776
Author(s):  
Takashi Hirayama
Keyword(s):  
Mitochondrial Gene ◽  
Plant Mitochondria ◽  
Short Review ◽  
Land Plant ◽  
Mrna Processing ◽  
Regulate Gene Expression ◽  
Double Stranded Dna ◽  
Regulatory Systems ◽  
Mrna Polyadenylation

Mitochondria have their own double-stranded DNA genomes and systems to regulate transcription, mRNA processing, and translation. These systems differ from those operating in the host cell, and among eukaryotes. In recent decades, studies have revealed several plant-specific features of mitochondrial gene regulation. The polyadenylation status of mRNA is critical for its stability and translation in mitochondria. In this short review, I focus on recent advances in understanding the mechanisms regulating mRNA polyadenylation in plant mitochondria, including the role of poly(A)-specific ribonuclease-like proteins (PARNs). Accumulating evidence suggests that plant mitochondria have unique regulatory systems for mRNA poly(A) status and that PARNs play pivotal roles in these systems.

Stress-Induced Changes in Ubiquinone Concentration and Alternative Oxidase in Plant Mitochondria

2001 ◽  
Vol 21 (3) ◽  
pp. 369-379 ◽  
Author(s):  
Vasily N. Popov ◽  
Albert C. Purvis ◽  
Vladimir P. Skulachev ◽  
Anneke M. Wagner
Keyword(s):  
Alternative Oxidase ◽  
Respiratory Activity ◽  
Plant Mitochondria ◽  
High Oxygen ◽  
Plant Tissues ◽  
Respiration Rates ◽  
Bell Peppers ◽  
Respiration Of Mitochondria ◽  
Induced Changes

We have investigated the influence of stress conditions such as incubation at 4°C and incubation in hyperoxygen atmosphere, on plant tissues. The ubiquinone (Q) content and respiratory activity of purified mitochondria was studied. The rate of respiration of mitochondria isolated from cold-treated green bell peppers (Capsicum annuum L) exceeds that of controls, but this is not so for mitochondria isolated from cold-treated cauliflower (Brassica oleracea L). Treatment with high oxygen does not alter respiration rates of cauliflower mitochondria. Analysis of kinetic data relating oxygen uptake with Q reduction in mitochondria isolated from tissue incubated at 4°C (bell peppers and cauliflowers) and at high oxygen levels (cauliflowers) reveals an increase in the total amount of Q and in the percentage of inoxidizable QH2. The effects are not invariably accompanied by an induction of the alternative oxidase (AOX). In those mitochondria where the AOX is induced (cold-treated bell pepper and cauliflower treated with high oxygen) superoxide production is lower than in the control. The role of reduced Q accumulation and AOX induction in the defense against oxidative damage is discussed.

Comparative Analysis of Autoxidation of Haemoglobin

2001 ◽  
Vol 204 (11) ◽  
pp. 2029-2033
Author(s):  
Frank B. Jensen
Keyword(s):  
Temperature Sensitivity ◽  
Oxidation Rate ◽  
Protective Role ◽  
Yellowfin Tuna ◽  
Histidine Residue ◽  
River Lamprey ◽  
Different Temperatures ◽  
Lower Temperature ◽  
The Impact

SUMMARY Autoxidation of oxyhaemoglobin (oxyHb) to methaemoglobin was measured at different temperatures in haemoglobin solutions from Atlantic hagfish, river lamprey, common carp, yellowfin tuna and pig. The aims were to evaluate the impact of the absent distal histidine in hagfish haemoglobin, the importance of oxyHb being either monomeric (hagfish and lamprey) or tetrameric (carp, tuna and pig) and to gain information on the temperature-sensitivity of autoxidation. The rate of autoxidation was lower in hagfish than in carp, yellowfin tuna and lamprey haemoglobins at any given temperature. Substitution of the distal histidine residue (His E7) with glutamine in hagfish haemoglobin was therefore not associated with an accelerated autoxidation, as might be expected on the basis of the normal protective role of His E7. Glutamine may have similar qualities to histidine and be involved in the low susceptibility to autoxidation. The low oxidation rate of hagfish haemoglobin, together with an oxidation rate of lamprey haemoglobin that did not differ from that of carp and yellowfin tuna haemoglobins, also revealed that autoxidation was not accelerated in the monomeric oxyhaemoglobins. Pig haemoglobin was oxidised more slowly than fish haemoglobins, demonstrating that fish haemoglobins are more sensitive to autoxidation than mammalian haemoglobins. The rate of autoxidation of hagfish haemoglobin was, however, only significantly greater than that of pig haemoglobin at high temperatures. Autoxidation was accelerated by rising temperature in all haemoglobins. Arrhenius plots of carp and yellowfin tuna haemoglobin revealed a break at 25°C, reflecting a lower temperature-sensitivity between 5 and 25°C than between 25 and 40°C.

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