Temperature Dependence of the Structure of the Substrate and Active Site of theThermus thermophilusChorismate Mutase E·S Complex†

Biochemistry ◽  
2006 ◽  
Vol 45 (28) ◽  
pp. 8562-8567 ◽  
Author(s):  
Zhang ◽  
Thomas C. Bruice
Keyword(s):  
Temperature Dependence ◽  
Active Site

scholarly journals Chemical mapping exposes the importance of active site interactions in governing the temperature dependence of enzyme turnover

2021 ◽  
Author(s):  
Samuel D Winter ◽  
Hannah BL Jones ◽  
Dora Rasadean ◽  
Rory Crean ◽  
Michael J. Danson ◽  
...  
Keyword(s):  
Heat Capacity ◽  
Temperature Dependence ◽  
Protein Dynamics ◽  
Active Site ◽  
Glucose Dehydrogenase ◽  
Global Changes ◽  
Global Dynamics ◽  
Specific Substrate ◽  
Substrate Interactions ◽  
Enzyme Turnover

Uncovering the role of global protein dynamics in enzyme turnover is needed to fully understand enzyme catalysis. Recently, we have demonstrated that the heat capacity of catalysis can reveal links between the protein free energy landscape, global protein dynamics and enzyme turnover, suggesting that subtle changes molecular interactions at the active site can affect long range protein dynamics and link to enzyme temperature activity. Here we use a model promiscuous enzyme (Glucose dehydrogenase from Sulfolobus Solfataricus) to chemically map how individual substrate interactions affect the temperature dependence of enzyme activity and the network of motions throughout the protein. Utilizing a combination of kinetics, REES spectroscopy and computational simulation we explore the complex relationship between enzyme-substrate interactions and the global dynamics of the protein. We find that changes in the heat capacity of catalysis and protein dynamics can be mapped to specific substrate-enzyme interactions. Our study reveals how subtle changes in substrate binding affect global changes in motion and flexibility extending throughout the protein.

Dynamic properties of the active site of azurin studied by the temperature dependence of the optical spectrum

1990 ◽  
Vol 3 (2) ◽  
pp. 77-79 ◽  
Author(s):  
Antonio Cupane ◽  
Maurizio Leone ◽  
Eugenio Vitrano ◽  
Lorenzo Cordone
Keyword(s):  
Temperature Dependence ◽  
Active Site ◽  
Optical Spectrum ◽  
Dynamic Properties

scholarly journals Chemical Mapping Exposes the Importance of Active Site Interactions in Governing the Temperature Dependence of Enzyme Turnover

ACS Catalysis ◽  
2021 ◽  
pp. 14854-14863
Author(s):  
Samuel D. Winter ◽  
Hannah B. L. Jones ◽  
Dora M. Răsădean ◽  
Rory M. Crean ◽  
Michael J. Danson ◽  
...  
Keyword(s):  
Temperature Dependence ◽  
Active Site ◽  
Chemical Mapping ◽  
Enzyme Turnover

Spin Label Studies on the Flavoproteins Lipoamide Dehydrogenase and D-Amino Acid Oxidase

1972 ◽  
Vol 27 (9) ◽  
pp. 1058-1062 ◽  
Author(s):  
H. J. Grande ◽  
A. J. W. G. Visser ◽  
J. L. De Wit ◽  
F. Müller ◽  
C. Veeger
Keyword(s):  
Amino Acid ◽  
Temperature Dependence ◽  
Active Site ◽  
Spin Label ◽  
Spin Labels ◽  
Acid Oxidase ◽  
Epr Spectrum ◽  
Amino Acid Oxidase ◽  
Lipoamide Dehydrogenase ◽  
Kinetics Of

Maleimide spin label was covalently bound to sulfhydryl residues of ᴅ-amino acid oxidase and lipoamide dehydrogenase. Labeling of native ᴅ-amino acid oxidase resulted in a non-homogeneous EPR-spectrum, which consisted of 4 moles of spin label bound immobile to the enzyme (mol.-weight 90.000). A detailed analysis of the spectrum, the kinetics of the reaction of the spin label with the protein and the temperature dependence of the spectrum showed that the spectrum originates from two different pairs of sulfhydryl groups. The spin labeled lipoamide dehydrogenase yielded also a mixed EPR-spectrum of two different bound spin labels, i.e. an immobile and a semimobile species. The temperature dependence gave for both types of spectra a transition point at 10°C. Titration with urea gave only for the immobile species a transition at 1.5 M. Part of the semimobile species seems to be bound near the active site.ᴅ-amino acid oxidase was also specifically labeled, near the active site, with a substrate analogue. From its EPR-spectrum it appeared that the analogue was bound very mobile (τc=0.3 nsec) with respect to the protein. Removal of FAD had a drastic reversible effect on the spectrum.

Temperature Dependence of the Critical Electron Dose for Fatty Acid Monolayers

1982 ◽  
Vol 40 ◽  
pp. 78-79
Author(s):  
Kenneth H. Downing ◽  
Robert M. Glaeser
Keyword(s):  
Electron Beam ◽  
Fatty Acid ◽  
Inelastic Scattering ◽  
Temperature Dependence ◽  
Structural Damage ◽  
Direct Result ◽  
Second Step ◽  
Strong Temperature Dependence ◽  
Electron Dose ◽  
Covalent Bonds

The structural damage of molecules irradiated by electrons is generally considered to occur in two steps. The direct result of inelastic scattering events is the disruption of covalent bonds. Following changes in bond structure, movement of the constituent atoms produces permanent distortions of the molecules. Since at least the second step should show a strong temperature dependence, it was to be expected that cooling a specimen should extend its lifetime in the electron beam. This result has been found in a large number of experiments, but the degree to which cooling the specimen enhances its resistance to radiation damage has been found to vary widely with specimen types.

Temperature Dependence of Magnetic Domains and Wall Structures

1972 ◽  
Vol 30 ◽  
pp. 496-497
Author(s):  
Sonoko Tsukahara ◽  
Tadami Taoka ◽  
Hisao Nishizawa
Keyword(s):  
Temperature Dependence ◽  
Domain Walls ◽  
Magnetic Domain ◽  
Iron Film ◽  
Objective Lens ◽  
Lorentz Microscopy ◽  
Domain Structures ◽  
Wall Structures ◽  
Crystal Films ◽  
Metallurgical Structure

The high voltage Lorentz microscopy was successfully used to observe changes with temperature; of domain structures and metallurgical structures in an iron film set on the hot stage combined with a goniometer. The microscope used was the JEM-1000 EM which was operated with the objective lens current cut off to eliminate the magnetic field in the specimen position. Single crystal films with an (001) plane were prepared by the epitaxial growth of evaporated iron on a cleaved (001) plane of a rocksalt substrate. They had a uniform thickness from 1000 to 7000 Å.The figure shows the temperature dependence of magnetic domain structure with its corresponding deflection pattern and metallurgical structure observed in a 4500 Å iron film. In general, with increase of temperature, the straight domain walls decrease in their width (at 400°C), curve in an iregular shape (600°C) and then vanish (790°C). The ripple structures with cross-tie walls are observed below the Curie temperature.

Locating Al in the DABCO catalyst before and after Al extraction

1990 ◽  
Vol 48 (4) ◽  
pp. 265-267
Author(s):  
Kathleen B. Reuter
Keyword(s):  
Active Site ◽  
Inverse Relationship ◽  
Transverse Direction ◽  
Reaction Rate ◽  
Acid Phosphate ◽  
Fracture Surfaces ◽  
Al Content ◽  
Before And After ◽  
Relationship Of

The reaction rate and efficiency of piperazine to 1,4-diazabicyclo-octane (DABCO) depends on the Si/Al ratio of the MFI topology catalysts. The Al was shown to be the active site, however, in the Si/Al range of 30-200 the reaction rate increases as the Si/Al ratio increases. The objective of this work was to determine the location and concentration of Al to explain this inverse relationship of Al content with reaction rate.Two silicalite catalysts in the form of 1/16 inch SiO2/Al2O3 bonded extrudates were examined: catalyst A with a Si/Al of 83; and catalyst B, the acid/phosphate Al extracted form of catalyst A, with a Si/Al of 175. Five extrudates from each catalyst were fractured in the transverse direction and particles were obtained from the fracture surfaces near the center of the extrudate diameter. Particles were also obtained from the outside surfaces of five extrudates.

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