Redox equilibria of manganese peroxidase from Phanerochaetes chrysosporium: functional role of residues on the proximal side of the haem pocket

2000 ◽  
Vol 349 (1) ◽  
pp. 85-90 ◽  
Author(s):  
Roberto SANTUCCI ◽  
Cristiana BONGIOVANNI ◽  
Stefano MARINI ◽  
Rebecca DEL CONTE ◽  
Ming TIEN ◽  
...  
Keyword(s):  
Manganese Peroxidase ◽  
Functional Role ◽  
Redox Properties ◽  
The Other ◽  
Redox Potentials ◽  
Protonation State ◽  
Alkaline Transition ◽  
Close Proximity ◽  
Redox Equilibria

Redox potentials of recombinant manganese peroxidase from Phanerochaetes chrysosporium have been measured by cyclic voltammetry as a function of pH, between pH 4.5 and pH 10.5. They display a bimodal behaviour (characterized by an ‘alkaline’ and an ‘acid’ transition), which indicates that (at least) two protonating groups change their pKb values upon reduction (and/or oxidation) of the iron atom in haem. Analogous measurements have been carried out on four site-directed mutants involving residues in close proximity to the proximal ligand, His173, in order to investigate the role played by residues of the proximal haem pocket on the redox properties of this enzyme. Results obtained suggest that the protonation state of N∆ of the proximal imidazole group is redox-linked and that it is crucial in regulating the ‘alkaline’ transition. On the other hand, none of the proximal mutants alters the ‘acid’ transition, suggesting that it is modulated by groups located in a different portion of the protein.

scholarly journals Redox equilibria of manganese peroxidase from Phanerochaetes chrysosporium: functional role of residues on the proximal side of the haem pocket

2000 ◽  
Vol 349 (1) ◽  
pp. 85 ◽  
Author(s):  
Roberto SANTUCCI ◽  
Cristiana BONGIOVANNI ◽  
Stefano MARINI ◽  
Rebecca DEL CONTE ◽  
Ming TIEN ◽  
...  
Keyword(s):  
Manganese Peroxidase ◽  
Functional Role ◽  
Proximal Side ◽  
Redox Equilibria

Modulatory role of a constitutively active population of α1D-adrenoceptors in conductance arteries

2002 ◽  
Vol 282 (2) ◽  
pp. H475-H481 ◽  
Author(s):  
Khalid Ziani ◽  
Regina Gisbert ◽  
Maria Antonia Noguera ◽  
Maria Dolores Ivorra ◽  
Pilar D'Ocon
Keyword(s):  
Mesenteric Artery ◽  
Functional Role ◽  
Mesenteric Arteries ◽  
The Other ◽  
Active Population ◽  
Abrupt Changes ◽  
Resting Tone ◽  
Constitutively Active

A constitutively active population of α1D-adrenoceptors in iliac and proximal, distal, and small mesenteric rat arteries was studied. The increase in resting tone (IRT) that evidences it was observed only in iliac and proximal mesenteric and was inhibited by prazosin (pIC50 = 9.57), 5-methylurapidil (pIC50 = 7.61), and BMY 7378 (pIC50 = 8.77). Chloroethylchlonidine (100 μmol/l) did not affect IRT, but when added before the other antagonists it blocked their effect. The potency shown by BMY 7378 confirms the α1D-subtype as responsible for IRT. BMY 7378 displayed greater inhibition of adrenergic responses in iliac (pIC50 = 7.57 ± 0.11) and proximal mesenteric arteries (pIC50 = 8.05 ± 0.2) than in distal (pIC50 = 6.94 ± 0.13) or small mesenteric arteries (pIC50 = 6.30 ± 0.14), which confirms the functional role of the α1D-adrenoceptor in iliac and proximal mesenteric arteries. This subtype prevents abrupt changes in iliac and proximal mesenteric artery caliber when the agonist disappears, and this modulatory role is evidenced by the slower decay in the response to norepinephrine after removal.

scholarly journals Redox Potentials of Disulfide Bonds in LOXL2 Studied by Nonequilibrium Alchemical Simulation

2021 ◽  
Vol 9 ◽  
Author(s):  
Lirui Lin ◽  
Haiying Zou ◽  
Wenjin Li ◽  
Li-Yan Xu ◽  
En-Min Li ◽  
...  
Keyword(s):  
Cancer Cells ◽  
Disulfide Bond ◽  
Disulfide Bonds ◽  
Functional Role ◽  
Catalytic Domain ◽  
Lysyl Oxidase ◽  
Scavenger Receptor ◽  
Redox Potentials ◽  
Catalytic Role

Lysyl oxidase-like 2 (LOXL2) is a metalloenzyme that catalyzes the oxidative deamination ε-amino group of lysine. It is found that LOXL2 is a promotor for the metastasis and invasion of cancer cells. Disulfide bonds are important components in LOXL2, and they play a stabilizing role for protein structure or a functional role for regulating protein bioactivity. The redox potential of disulfide bond is one important property to determine the functional role of disulfide bond. In this study, we have calculated the reduction potential of all the disulfide bonds in LOXL2 by non-equilibrium alchemical simulations. Our results show that seven of seventeen disulfide bonds have high redox potentials between −182 and −298 mV and could have a functional role, viz., Cys573–Cys625, Cys579–Cys695, Cys657–Cys673, and Cys663–Cys685 in the catalytic domain, Cys351–Cys414, Cys464–Cys530, and Cys477–Cys543 in the scavenger receptor cysteine-rich (SRCR) domains. The disulfide bond of Cys351–Cys414 is predicted to play an allosteric function role, which could affect the metastasis and invasion of cancer cells. Other functional bonds have a catalytic role related to enzyme activity. The rest of disulfide bonds are predicted to play a structural role. Our study provides an important insight for the classification of disulfide bonds in LOXL2 and can be utilized for the drug design that targets the cysteine residues in LOXL2.

scholarly journals SUMOylome Modulates Intraflagellar Transport Machinery and Eukaryotic Cilia Motility

2021 ◽  
Author(s):  
Komal Sharma ◽  
Irina Sizova ◽  
Girdhar Pandey ◽  
Peter Hegemann ◽  
Suneel Kateriya
Keyword(s):  
Functional Role ◽  
Intraflagellar Transport ◽  
Small Gtpase ◽  
The Other ◽  
Signaling Proteins ◽  
Sumoylation Site ◽  
C Terminus ◽  
First Time ◽  
Insight Into

Abstract Translocation of channelrhodopsins (ChRs) is mediated by intraflagellar transport (IFT) machinery. However, the functional role of the network containing photoreceptors, IFT and other proteins in controlling cilia motility of the alga is still not fully delineated. In the current study, we identified two important motifs at the C-terminus of ChR1. One of them is similar to a known ciliary targeting sequence that specifically interacts with a small GTPase, and the other is a SUMOylation site. For the first time, experimental data provide an insight into the role of SUMOylation in the modulation of IFT & ChR1. Blocking of SUMOylation affected the phototaxis of C. reinhardtii cells. This implies SUMOylation based regulation of protein network controlling photomotility. The conservation of SUMOylation site pattern as analyzed for the relevant photoreceptors, IFT and its associated signaling proteins in other ciliated green algae suggested SUMOylation based photobehavioural response across the microbes. This report establishes a link between evolutionary conserved SUMOylation and ciliary machinery for the maintenance and functioning of cilia across the eukaryotes. Our enriched SUMOylome of C. reinhardtii comprehends the proteins related to ciliary development and, photo-signaling, along with homologue(s) associated to human ciliopathies as SUMO targets.

scholarly journals The hidden links between animal weapons, fighting style and their expression on contest resolution

2020 ◽  
Author(s):  
Alexandre V. Palaoro ◽  
Paulo E. C. Peixoto
Keyword(s):  
Body Size ◽  
Functional Role ◽  
Meta Analysis ◽  
The Other ◽  
List Type ◽  
Relative Importance ◽  
Animal Kingdom ◽  
Internal Morphology ◽  
Contest Outcome

SUMMARYIn many species that fight over resources, individuals use specialized structures to overpower their rivals (i.e. weapons). Despite their similar roles for contest settlement (i.e. affecting the winning chances), weapons are highly diverse morphological structures across species. However, the comprehension on how this diversity evolved is still open for debate.Unfortunately, most studies on how weapons are used during contests focus on size asymmetries between winners and losers. Although such information is important to understand, it does not provide much information regarding the mechanisms promoting weapon diversification. In addition, in many situations, the effect of weapon size on contest resolution may be confounded with the effect of body size due to allometric correlations.One way to decompose the relative importance of weapon and body size on contest outcome is to focus on the functional role of weapons. That is, investigate the function of the weapon during contests, and how size should affect its function.We propose two hypotheses that explicitly associate how weapon function may determine the relative importance of weapon and body size in affecting rivals during contests. One based on the internal morphology of the weapon – whether muscles are within the weapon or not – and the other based on fighting style – whether the weapon is used to injure the rival or not.To test our hypotheses, we developed a meta-analysis spanning 31 genera across the animal kingdom.We found that internal morphology and fighting style are important to determine the relative importance of weapon and body size on contest resolution. Weapons that do not have muscles within them (e.g., horns) affect more the chance of winning than weapons that have muscles within them (e.g., claws). Similarly, weapons used to throw/push rivals away (e.g., oversized mandibles) affect more the chance of winning than those used to make the rival flee (e.g., jaws).Overall, we have shown that weapon usage (i.e. weapon function) may affect weapon evolution in predictable ways: weapons without muscles and using for pushing may be selected for size, while muscled weapons used for injuring may be selected for strength.

Effect of protonation, composition and isomerism on the redox properties and electron (de)localization of classical polyoxometalates

2017 ◽  
Vol 2 (11) ◽  
Author(s):  
Xavier López
Keyword(s):  
Inorganic Compounds ◽  
Redox Properties ◽  
Theoretical Research ◽  
Redox Activity ◽  
Redox Potentials ◽  
Transition Metal Atoms ◽  
Computational Data ◽  
Keggin Anions ◽  
Dawson Structure

Abstract This publication reviews some relevant features related with the redox activity of two inorganic compounds: [XM12O40]q- (Keggin structure) and [X2M18O62]q- (Wells-Dawson structure). These are two well-known specimens of the vast Polyoxometalate (POM) family, which has been the subject of extensive experimental and theoretical research owing to their unmatched properties. In particular, their redox activity focus a great deal of attention from scientists due to their prospective related applications. POMs are habitually seen as ‘electron sponges’ since many of them accept several electrons without losing their chemical identity. This makes them excellent models to study mechanisms of electrochemical nature. Their redox properties depend on: (i) the type and number of transition metal atoms in the structure, (ii) the basicity of the first reduced species and, occasionally, of the fully oxidized species; (iii) the size of the molecule, (iv) the overall negative charge of the POM, and (v) the size of the central heteroatom. In the last years, important collaboration between the experimental and theoretical areas has been usual on the development of POM science. In the present chapter three of these synergies are highlighted: the influence of the internal heteroatom upon the redox potentials of Keggin anions; the dependence of the redox waves of Fe-substituted Wells-Dawson compounds with pH; and the role of electron delocalization and pairing in mixed-metal Mo/W Wells-Dawson compounds in their ability to accept electrons. In these three cases, a complete understanding of the problem would not have been possible without the mutual benefit of experimental and computational data.

Bridging the gap between the other and me: the functional role of motor resonance and action effects in infants’ imitation

2011 ◽  
Vol 14 (4) ◽  
pp. 901-910 ◽  
Author(s):  
Markus Paulus ◽  
Sabine Hunnius ◽  
Marlies Vissers ◽  
Harold Bekkering
Keyword(s):  
Functional Role ◽  
The Other ◽  
Motor Resonance ◽  
Action Effects

scholarly journals STUDIES ON IMMUNE HUMAN HEMOLYSIS

1961 ◽  
Vol 113 (1) ◽  
pp. 193-218 ◽  
Author(s):  
Carl F. Hinz ◽  
Mary E. Picken ◽  
Irwin H. Lepow
Keyword(s):  
Mechanism Of Action ◽  
Human Disease ◽  
Esterase Activity ◽  
Functional Role ◽  
Disease State ◽  
The Other ◽  
Human Model ◽  
Human Complement ◽  
Serum Inhibitor

1. The inactivation, of C'1 blocks the completion of the cold phase of the Donath-Landsteiner reaction; inactivation of the other components of complement does not interfere with the cold phase of the reaction. 2. C'2, C'3, and C'4 are required for the completion of the hemolytic reaction. C'4 reacts in either the cold or warm phase, but C'2 and C'3 must react in the warm phase. 3. Partially purified C'1 or C'1 esterase can be substituted for whole serum in the cold phase, although neither reagent contains any of the other components of complement 4. Partially purified serum inhibitor of C'1 esterase blocks the effect of C'1 esterase in the cold phase, and reverses the effect of complement, C'1 or C'1 esterase when incubated with "activated" cells after the cold phase. 5. C'1 esterase activity can be eluted from "activated" erythrocytes with Na3EDTA. 6. The components of human complement in this human hemolytic reaction act in the order C'1, C'4, C'2, C'3. Ca++ is required for the reaction with C'1, and Mg++ is required for the reaction with C'2. 7. Accordingly, a functional role of C'1 esterase in a human disease state is demonstrated, and a human model is established for the study of the mechanism of action of complement.

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