scholarly journals Emergence of a Negative Activation Heat Capacity during Evolution of a Designed Enzyme

2019 ◽  
Vol 141 (30) ◽  
pp. 11745-11748 ◽  
Author(s):  
H. Adrian Bunzel ◽  
Hajo Kries ◽  
Luca Marchetti ◽  
Cathleen Zeymer ◽  
Peer R. E. Mittl ◽  
...  
Keyword(s):  
Heat Capacity ◽  
Activation Heat

scholarly journals pH-Independent Heat Capacity Changes during Phosphorolysis Catalyzed by the Pyrimidine Nucleoside Phosphorylase from Geobacillus thermoglucosidasius

2021 ◽  
Author(s):  
Felix Kaspar ◽  
Darian S. Wolff ◽  
Peter Neubauer ◽  
Anke Kurreck ◽  
Vickery Arcus
Keyword(s):  
Heat Capacity ◽  
Reaction System ◽  
Heat Capacity Change ◽  
Pyrimidine Nucleoside ◽  
Nucleoside Phosphorylase ◽  
Geobacillus Thermoglucosidasius ◽  
Capacity Change ◽  
Pyrimidine Nucleoside Phosphorylase ◽  
Enzyme Catalyzed Reactions ◽  
Activation Heat

Enzyme-catalyzed reactions sometimes display curvature in their Eyring plots in the absence of denaturation, indicative of a change in activation heat capacity. However, pH and (de)protonation effects on this phenomenon have remained unexplored. Herein, we report a kinetic characterization of the thermophilic pyrimidine nucleoside phosphorylase from <i>Geobacillus thermoglucosidasius</i> across a two-dimensional working space covering 35 °C and 3 pH units with two substrates displaying different pK<sub>a</sub> values. Our analysis revealed the presence of a measurable activation heat capacity change in this reaction system, which showed no significant dependence on medium pH or substrate charge. Our results further describe the remarkable effects of a single halide substitution which has a minor influence on the heat capacity change but conveys a significant kinetic effect by lowering the activation enthalpy, causing a >10-fold rate increase. Collectively, our results present an important piece in the understanding of enzymatic systems across multidimensional working spaces where the choice of reaction condition can affect rate, affinity and thermodynamic phenomena independently of one another.<br>

scholarly journals Polarimetric Determination of Activation Heat Capacity (DeltaCp*).

1981 ◽  
Vol 35b ◽  
pp. 357-366
Author(s):  
Christer Albano ◽  
Svante Wold ◽  
Henning Thøgersen ◽  
Povl Krogsgaard-Larsen ◽  
Ulrika Örn
Keyword(s):  
Heat Capacity ◽  
Activation Heat

scholarly journals Rigidifying a De Novo Enzyme Increases Activity and Induces a Negative Activation Heat Capacity

ACS Catalysis ◽  
2021 ◽  
pp. 11532-11541
Author(s):  
Sarah A. Hindson ◽  
H. Adrian Bunzel ◽  
Bettina Frank ◽  
Dimitri A. Svistunenko ◽  
Christopher Williams ◽  
...  
Keyword(s):  
Heat Capacity ◽  
De Novo ◽  
Activation Heat

scholarly journals pH-Independent Heat Capacity Changes during Phosphorolysis Catalyzed by the Pyrimidine Nucleoside Phosphorylase from Geobacillus thermoglucosidasius

2021 ◽  
Author(s):  
Felix Kaspar ◽  
Darian S. Wolff ◽  
Peter Neubauer ◽  
Anke Kurreck ◽  
Vickery Arcus
Keyword(s):  
Heat Capacity ◽  
Reaction System ◽  
Heat Capacity Change ◽  
Pyrimidine Nucleoside ◽  
Nucleoside Phosphorylase ◽  
Geobacillus Thermoglucosidasius ◽  
Capacity Change ◽  
Pyrimidine Nucleoside Phosphorylase ◽  
Enzyme Catalyzed Reactions ◽  
Activation Heat

Enzyme-catalyzed reactions sometimes display curvature in their Eyring plots in the absence of denaturation, indicative of a change in activation heat capacity. However, pH and (de)protonation effects on this phenomenon have remained unexplored. Herein, we report a kinetic characterization of the thermophilic pyrimidine nucleoside phosphorylase from <i>Geobacillus thermoglucosidasius</i> across a two-dimensional working space covering 35 °C and 3 pH units with two substrates displaying different pK<sub>a</sub> values. Our analysis revealed the presence of a measurable activation heat capacity change in this reaction system, which showed no significant dependence on medium pH or substrate charge. Our results further describe the remarkable effects of a single halide substitution which has a minor influence on the heat capacity change but conveys a significant kinetic effect by lowering the activation enthalpy, causing a >10-fold rate increase. Collectively, our results present an important piece in the understanding of enzymatic systems across multidimensional working spaces where the choice of reaction condition can affect rate, affinity and thermodynamic phenomena independently of one another.<br>

scholarly journals Dynamical origins of heat capacity changes in enzyme catalysed reactions

2017 ◽  
Author(s):  
Marc W van der Kamp ◽  
Erica J. Prentice ◽  
Kirsty L. Kraakmann ◽  
Michael Connolly ◽  
Adrian J. Mulholland ◽  
...  
Keyword(s):  
Heat Capacity ◽  
Active Site ◽  
Reaction Rates ◽  
Heat Capacity Change ◽  
Catalysed Reaction ◽  
Capacity Change ◽  
Heat Capacity Changes ◽  
Dynamics Simulations ◽  
Alpha Glucosidase ◽  
Activation Heat

AbstractHeat capacity changes are emerging as essential for explaining the temperature dependence of enzyme-catalysed reaction rates. This has important implications for enzyme kinetics, thermoadaptation and evolution, but the physical basis of these heat capacity changes is unknown. Here we show by a combination of experiment and simulation, for two quite distinct enzymes (dimeric ketosteroid isomerase and monomeric alpha-glucosidase), that the activation heat capacity change for the catalysed reaction can be predicted through atomistic molecular dynamics simulations. The simulations reveal subtle and surprising underlying dynamical changes: tightening of loops around the active site is observed as expected, but crucially, changes in energetic fluctuations are evident across the whole enzyme including important contributions from oligomeric neighbours and domains distal to the active site. This has general implications for understanding enzyme catalysis and demonstrating a direct connection between functionally important microscopic dynamics and macroscopically measurable quantities.

scholarly journals Evolution of dynamical networks enhances catalysis in a designer enzyme

2020 ◽  
Author(s):  
H. Adrian Bunzel ◽  
J. L. Ross Anderson ◽  
Donald Hilvert ◽  
Vickery L. Arcus ◽  
Marc W. van der Kamp ◽  
...  
Keyword(s):  
Heat Capacity ◽  
Transition State ◽  
Physical Origin ◽  
Original Design ◽  
State Ensemble ◽  
Dynamics Simulations ◽  
Evolutionary Tuning ◽  
Transition State Ensemble ◽  
Activation Heat

AbstractActivation heat capacity is emerging as a crucial factor in enzyme thermoadaptation, as shown by non-Arrhenius behaviour of many natural enzymes1,2. However, its physical origin and relationship to evolution of catalytic activity remain uncertain. Here, we show that directed evolution of a computationally designed Kemp eliminase introduces dynamical changes that give rise to an activation heat capacity absent in the original design3. Extensive molecular dynamics simulations show that evolution results in the closure of solvent exposed loops and better packing of the active site with transition state stabilising residues. Remarkably, these changes give rise to a correlated dynamical network involving the transition state and large parts of the protein. This network tightens the transition state ensemble, which induces an activation heat capacity and thereby nonlinearity in the temperature dependence. Our results have implications for understanding enzyme evolution (e.g. in explaining the role of distal mutations and evolutionary tuning of dynamical responses) and suggest that integrating dynamics with design and evolution will accelerate the development of efficient novel enzymes.

HEAT CAPACITY MEASUREMENTS ON THE DILUTED ISING SYSTEM Cs3CopZn1-pCl5

1971 ◽  
Vol 32 (C1) ◽  
pp. C1-1008-C1-1009 ◽  
Author(s):  
E. LAGENDIJK ◽  
W. J. HUISKAMP ◽  
P. F. BONGERS
Keyword(s):  
Heat Capacity ◽  
Ising System ◽  
Heat Capacity Measurements

HEAT CAPACITY OF NEODYMIUM BELOW 10 K

1978 ◽  
Vol 39 (C6) ◽  
pp. C6-794-C6-795 ◽  
Author(s):  
E. M. Forgan ◽  
C. M. Muirhead
Keyword(s):  
Heat Capacity

TEMPERATURE-LINEAR TERM OF HEAT CAPACITY OF La-Ba-Cu-O AND La-Sr-Cu-O SYSTEMS

1988 ◽  
Vol 49 (C8) ◽  
pp. C8-2133-C8-2134
Author(s):  
K. Kumagai ◽  
Y. Nakamura ◽  
I. Watanabe ◽  
Y. Nakamichi ◽  
H. Nakajima
Keyword(s):  
Heat Capacity ◽  
Linear Term
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