Folding mechanism of Pseudomonas aeruginosa cytochrome c 551 : role of electrostatic interactions on the hydrophobic collapse and transition state properties 1 1Edited by P. E. Wright

1999 ◽  
Vol 289 (5) ◽  
pp. 1459-1467 ◽  
Author(s):  
Carlo Travaglini-Allocatelli ◽  
Francesca Cutruzzolà ◽  
Maria Giulia Bigotti ◽  
Rosemary A. Staniforth ◽  
Maurizio Brunori
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Cytochrome C ◽  
Transition State ◽  
Electrostatic Interactions ◽  
Hydrophobic Collapse ◽  
Folding Mechanism

scholarly journals Dramatic shape changes occur as Cytochrome c folds

2020 ◽  
Author(s):  
Serdal Kirmizialtin ◽  
Felicia Pitici ◽  
Alfredo E Cardenas ◽  
Ron Elber ◽  
D. Thirumalai
Keyword(s):  
Cytochrome C ◽  
Experimental Studies ◽  
Quantitative Agreement ◽  
Time Dependent ◽  
Native State ◽  
Time Resolved ◽  
Hydrophobic Collapse ◽  
Folding Mechanism ◽  
Cyt C ◽  
Shape Changes

AbstractExtensive experimental studies on the folding of Cytochrome c (Cyt c) make this small protein an ideal target for atomic detailed simulations for the purposes of quantitatively characterizing the structural transitions and the associated time scales for folding to the native state from an ensemble of unfolded states. We use previously generated atomically detailed folding trajectories by the Stochastic Difference Equation in Length (SDEL) to calculate the time-dependent changes in the Small Angle X-ray scattering (SAXS) profiles. Excellent agreement is obtained between experiments and simulations for the time dependent SAXS spectra, allowing us to identify the structures of the folding intermediates, which shows that Cyt c reaches the native state by a sequential folding mechanism. Using the ensembles of structures along the folding pathways we show that compaction and the sphericity of Cyt c change dramatically from the prolate ellipsoid shape in the unfolded state to the spherical native state. Our data, which provides unprecedented quantitative agreement with all aspects of time-resolved SAXS experiments, shows that hydrophobic collapse and amide group protection coincide on the 100 microseconds time scale, which is in accord with ultrafast Hydrogen/Deuterium exchange studies. Based on these results we propose that compaction of polypeptide chains, accompanied by dramatic shape changes, is a universal characteristic of globular proteins, regardless of the underlying folding mechanism.

Models for the Role of Magnesium in Enzymic Catalysis. The Effect of Magnesium Ion on the General Base Catalyzed Enolization of Methyl Acetonylphosphonate

1975 ◽  
Vol 53 (15) ◽  
pp. 2354-2358 ◽  
Author(s):  
Ronald Kluger ◽  
Andrea Wayda
Keyword(s):  
Transition State ◽  
Rate Constant ◽  
Electrostatic Interactions ◽  
Magnesium Ion ◽  
Electrostatic Effects ◽  
Experimental Conditions ◽  
General Base ◽  
Rate Determining Step

Magnesium ion promotes the general base catalyzed iodination of methyl acetonylphosphonate (MAP), 1. Although the concentration of complex is very low, definite rate constant increases are observed. The rate determining step under the experimental conditions is enolization of the substrate. Acceleration is observed for both charged and uncharged bases. The acceleration for charged bases is about twice that for uncharged bases. Thus, electrostatic effects are probably important but not exclusive. It is proposed that efficient catalysis by magnesium ion in related enzymic reactions is a consequence of the ability of magnesium ion to form a stabilizing complex with an enolate-like transition state and to reduce repulsive electrostatic interactions of the substrate and a catalytic base.

Activation of cytochrome c to a peroxidase compound I-type intermediate by H2O2: relevance to redox signalling in apoptosis

2004 ◽  
Vol 71 ◽  
pp. 97-106 ◽  
Author(s):  
Mark Burkitt ◽  
Clare Jones ◽  
Andrew Lawrence ◽  
Peter Wardman
Keyword(s):  
Cytochrome C ◽  
Hydroxyl Radical ◽  
Redox Regulation ◽  
Chemotherapeutic Agents ◽  
Tyrosyl Radical ◽  
Compound I ◽  
Definitive Evidence ◽  
Enhanced Production ◽  
Physico Chemical

The release of cytochrome c from mitochondria during apoptosis results in the enhanced production of superoxide radicals, which are converted to H2O2 by Mn-superoxide dismutase. We have been concerned with the role of cytochrome c/H2O2 in the induction of oxidative stress during apoptosis. Our initial studies showed that cytochrome c is a potent catalyst of 2′,7′-dichlorofluorescin oxidation, thereby explaining the increased rate of production of the fluorophore 2′,7′-dichlorofluorescein in apoptotic cells. Although it has been speculated that the oxidizing species may be a ferryl-haem intermediate, no definitive evidence for the formation of such a species has been reported. Alternatively, it is possible that the hydroxyl radical may be generated, as seen in the reaction of certain iron chelates with H2O2. By examining the effects of radical scavengers on 2′,7′-dichlorofluorescin oxidation by cytochrome c/H2O2, together with complementary EPR studies, we have demonstrated that the hydroxyl radical is not generated. Our findings point, instead, to the formation of a peroxidase compound I species, with one oxidizing equivalent present as an oxo-ferryl haem intermediate and the other as the tyrosyl radical identified by Barr and colleagues [Barr, Gunther, Deterding, Tomer and Mason (1996) J. Biol. Chem. 271, 15498-15503]. Studies with spin traps indicated that the oxo-ferryl haem is the active oxidant. These findings provide a physico-chemical basis for the redox changes that occur during apoptosis. Excessive changes (possibly catalysed by cytochrome c) may have implications for the redox regulation of cell death, including the sensitivity of tumour cells to chemotherapeutic agents.

Role of rhizobia in suppressing the root rot and root knot disease of chili used alone or with Pseudomonas aeruginosa

2019 ◽  
Vol 52 (3) ◽  
Author(s):  
Gulnaz Parveen ◽  
Faizah Urooj ◽  
Hafiza Asma Shafique ◽  
Afshan Rahman ◽  
Syed Ehteshamul Haque
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Root Rot
Sign in / Sign up

Export Citation Format

Share Document