scholarly journals Kramers’ Theory and the Dependence of Enzyme Dynamics on Trehalose-Mediated Viscosity

Catalysts ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 659 ◽  
Author(s):  
José G. Sampedro ◽  
Miguel A. Rivera-Moran ◽  
Salvador Uribe-Carvajal
Keyword(s):  
Protein Dynamics ◽  
Protein Function ◽  
Thermal Inactivation ◽  
Hydration Shell ◽  
Protein Stabilization ◽  
Enzyme Dynamics ◽  
Enzyme Protein ◽  
Trehalose Biosynthesis ◽  
And Function ◽  
Relationship Of

The disaccharide trehalose is accumulated in the cytoplasm of some organisms in response to harsh environmental conditions. Trehalose biosynthesis and accumulation are important for the survival of such organisms by protecting the structure and function of proteins and membranes. Trehalose affects the dynamics of proteins and water molecules in the bulk and the protein hydration shell. Enzyme catalysis and other processes dependent on protein dynamics are affected by the viscosity generated by trehalose, as described by the Kramers’ theory of rate reactions. Enzyme/protein stabilization by trehalose against thermal inactivation/unfolding is also explained by the viscosity mediated hindering of the thermally generated structural dynamics, as described by Kramers’ theory. The analysis of the relationship of viscosity–protein dynamics, and its effects on enzyme/protein function and other processes (thermal inactivation and unfolding/folding), is the focus of the present work regarding the disaccharide trehalose as the viscosity generating solute. Finally, trehalose is widely used (alone or in combination with other compounds) in the stabilization of enzymes in the laboratory and in biotechnological applications; hence, considering the effect of viscosity on catalysis and stability of enzymes may help to improve the results of trehalose in its diverse uses/applications.

Preparation and Characterization of β-glucosidase Films for Stabilization and Handling in Dry Configurations

2020 ◽  
Vol 21 (8) ◽  
pp. 741-747
Author(s):  
Liguang Zhang ◽  
Yanan Shen ◽  
Wenjing Lu ◽  
Lengqiu Guo ◽  
Min Xiang ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Protein Function ◽  
Protein Stabilization ◽  
Functional Protein ◽  
Elongation At Break ◽  
Gelatin Films ◽  
The Stability ◽  
And Function ◽  
General Method

Background: Although the stability of proteins is of significance to maintain protein function for therapeutical applications, this remains a challenge. Herein, a general method of preserving protein stability and function was developed using gelatin films. Method: Enzymes immobilized onto films composed of gelatin and Ethylene Glycol (EG) were developed to study their ability to stabilize proteins. As a model functional protein, β-glucosidase was selected. The tensile properties, microstructure, and crystallization behavior of the gelatin films were assessed. Result: Our results indicated that film configurations can preserve the activity of β-glucosidase under rigorous conditions (75% relative humidity and 37°C for 47 days). In both control films and films containing 1.8 % β-glucosidase, tensile strength increased with increased EG content, whilst the elongation at break increased initially, then decreased over time. The presence of β-glucosidase had a negligible influence on tensile strength and elongation at break. Scanning electron-microscopy (SEM) revealed that with increasing EG content or decreasing enzyme concentrations, a denser microstructure was observed. Conclusion: In conclusion, the dry film is a promising candidate to maintain protein stabilization and handling. The configuration is convenient and cheap, and thus applicable to protein storage and transportation processes in the future.

PROTEIN DYNAMICS IN PHOSPHORYLATION-MEDIATED ALLOSTERY PROBED BY AMIDE EXCHANGE MASS SPECTROMETRY

COSMOS ◽  
2013 ◽  
Vol 09 (01) ◽  
pp. 19-27
Author(s):  
MADHUBRATA GHOSH ◽  
GANESH S. ANAND
Keyword(s):  
Mass Spectrometry ◽  
Protein Dynamics ◽  
Protein Function ◽  
Post Translational Modifications ◽  
Exchange Mass Spectrometry ◽  
Amide Exchange ◽  
Hydrogen Deuterium ◽  
Deuterium Exchange Mass Spectrometry ◽  
And Function

A major goal of molecular biology is to correlate molecular structure with function. Since most enzymes and biological catalysts are proteins, the focus for correlating 'form' with 'function' has been entirely on protein macromolecular structure. It is obvious that any understanding of protein function must come through an understanding protein dynamics. Furthermore, all of the regulatory reactions are through changes in dynamics brought about by post-translational modifications, the most important of which is phosphorylation. This review highlights the important role of covalent phosphorylation and noncovalent phosphates in regulating allosteric effects and function through a study of protein dynamics. Mass spectrometry is a relatively new and increasingly important tool for describing protein dynamics. All examples described in this review have been studied by amide hydrogen/deuterium exchange mass spectrometry.

scholarly journals Protein dynamics and function from solution state NMR spectroscopy

2016 ◽  
Vol 49 ◽  
Author(s):  
Michael Kovermann ◽  
Per Rogne ◽  
Magnus Wolf-Watz
Keyword(s):  
Nmr Spectroscopy ◽  
Protein Dynamics ◽  
Conformational Changes ◽  
Protein Function ◽  
Time Intervals ◽  
Energy Landscape Theory ◽  
Nmr Techniques ◽  
Dynamics And Function ◽  
And Function ◽  
Design Experiments

AbstractIt is well-established that dynamics are central to protein function; their importance is implicitly acknowledged in the principles of the Monod, Wyman and Changeux model of binding cooperativity, which was originally proposed in 1965. Nowadays the concept of protein dynamics is formulated in terms of the energy landscape theory, which can be used to understand protein folding and conformational changes in proteins. Because protein dynamics are so important, a key to understanding protein function at the molecular level is to design experiments that allow their quantitative analysis. Nuclear magnetic resonance (NMR) spectroscopy is uniquely suited for this purpose because major advances in theory, hardware, and experimental methods have made it possible to characterize protein dynamics at an unprecedented level of detail. Unique features of NMR include the ability to quantify dynamics (i) under equilibrium conditions without external perturbations, (ii) using many probes simultaneously, and (iii) over large time intervals. Here we review NMR techniques for quantifying protein dynamics on fast (ps-ns), slow (μs-ms), and very slow (s-min) time scales. These techniques are discussed with reference to some major discoveries in protein science that have been made possible by NMR spectroscopy.

scholarly journals What Happened to Your College Town: The Changing Relationship of Higher Education and College Towns, 1940–2000

2021 ◽  
Vol 61 (3) ◽  
pp. 320-340
Author(s):  
Kate Rousmaniere
Keyword(s):  
Higher Education ◽  
Higher Education Institutions ◽  
History Of Higher Education ◽  
Campus Housing ◽  
College Towns ◽  
Education Enrollment ◽  
History Of ◽  
To Come ◽  
And Function ◽  
Relationship Of

AbstractThis essay examines the history of what is commonly called the town-gown relationship in American college towns in the six decades after the Second World War. A time of considerable expansion of higher education enrollment and function, the period also marks an increasing detachment of higher education institutions from their local communities. Once closely tied by university offices that advised the bulk of their students in off-campus housing, those bonds between town and gown began to come apart in the 1970s, due primarily to legal and economic factors that restricted higher education institutions’ outreach. Given the importance of off-campus life to college students, over half of whom have historically lived off campus, the essay argues for increased research on college towns in the history of higher education.

scholarly journals Molecular and Pharmacological Characterization of the Interaction between Human Geranylgeranyltransferase Type I and Ras-Related Protein Rap1B

2021 ◽  
Vol 22 (5) ◽  
pp. 2501
Author(s):  
Sonja Hinz ◽  
Dominik Jung ◽  
Dorota Hauert ◽  
Hagen S. Bachmann
Keyword(s):  
Protein Function ◽  
Tumor Development ◽  
Cysteine Residue ◽  
Type I ◽  
Pharmacological Characterization ◽  
Anti Cancer ◽  
And Function ◽  
Caax Motif ◽  
Important Drug

Geranylgeranyltransferase type-I (GGTase-I) represents an important drug target since it contributes to the function of many proteins that are involved in tumor development and metastasis. This led to the development of GGTase-I inhibitors as anti-cancer drugs blocking the protein function and membrane association of e.g., Rap subfamilies that are involved in cell differentiation and cell growth. In the present study, we developed a new NanoBiT assay to monitor the interaction of human GGTase-I and its substrate Rap1B. Different Rap1B prenylation-deficient mutants (C181G, C181S, and ΔCQLL) were designed and investigated for their interaction with GGTase-I. While the Rap1B mutants C181G and C181S still exhibited interaction with human GGTase-I, mutant ΔCQLL, lacking the entire CAAX motif (defined by a cysteine residue, two aliphatic residues, and the C-terminal residue), showed reduced interaction. Moreover, a specific, peptidomimetic and competitive CAAX inhibitor was able to block the interaction of Rap1B with GGTase-I. Furthermore, activation of both Gαs-coupled human adenosine receptors, A2A (A2AAR) and A2B (A2BAR), increased the interaction between GGTase-I and Rap1B, probably representing a way to modulate prenylation and function of Rap1B. Thus, A2AAR and A2BAR antagonists might be promising candidates for therapeutic intervention for different types of cancer that overexpress Rap1B. Finally, the NanoBiT assay provides a tool to investigate the pharmacology of GGTase-I inhibitors.

scholarly journals RELATION OF ADRENAL CORTICAL HORMONE TO LYMPHOID TISSUE AND LYMPHOCYTES

Blood ◽  
1948 ◽  
Vol 3 (7) ◽  
pp. 729-754 ◽  
Author(s):  
WILLIAM N. VALENTINE ◽  
CHARLES G. CRADDOCK ◽  
JOHN S. LAWRENCE
Keyword(s):  
Adrenal Cortex ◽  
Lymphoid Tissue ◽  
Hormonal Control ◽  
Tissue Structure ◽  
Lymphoid Tissues ◽  
Adrenal Cortical Hormone ◽  
Cortical System ◽  
And Function ◽  
Relationship Of ◽  
The Relationship

Abstract The hormonal control through the hypophyseo-adrenal cortical system of lymphoid tissue structure and function is an important concept. We cannot at the present time regard that the concept is established fact. Final judgment must await additional work and the clarification of some of the inconsistencies which appear to exist. It seems reasonable that lymphoid tissue is one of the end organs of adrenal cortical hormone and that it may perhaps play a role in the response of the organism to stress. It seems quite clear that the sugar hormone of the adrenal cortex is capable of producing structural alterations in lymphoid tissue. Change in thoracic duct lymphocyte numbers as a result of augmentation in the amount of available adrenal cortical hormone is at present controversial. Experiments in this laboratory have failed to demonstrate it. The production of lymphopenia, at least in some species and possibly in man, by increasing available sugar hormone is supported by some evidence. The exact mechanism of production of lymphopenia is open to question, its relationship to changes in lymphoid tissue structure being one of inference. The converse situation—absolute lympocytosis resulting from deprivation of adrenal cortical hormone—is the subject of controversial reports. At best, it must be admitted that relatively slight alterations from the accepted normal range of lymphocyte values occur in the adrenal insufficient organism. Changes in plasma gamma globulins and antibody titers associated with changes in the amount of available cortical hormone are reported. It should be clarified whether such changes have necessarily resulted from lymphocyte dissolution or are related to other of the variegated actions of adrenal cortical hormone. The relationship of adrenal cortical hormone to lymphoid tissue and lymphocytes and the relationship of the latter to the response of the organism to stress must indeed be complex. It is reasonably well established that the life span of the lymphocyte is very short indeed1,58,22 and each lymphocyte presumably liberates its metabolically important contents within a few hours at the most. If stress continues for any period of time, as often it does, it is difficult to visualize the wisdom of interfering with the production of metabolically vital substances in order to secure the transient benefits of lymphoid tissue dissolution. It is also somewhat difficult to regard as proved that the various changes reported after hormone augmentation or deprivation necessarily represent the normal mechanism by which these factors are regulated and kept within physiologic limits. More investigations are required to answer such questions and to further elucidate the interrelationship of the adrenal cortex and lymphoid tissues.

scholarly journals Dynamics and mechanism of ultrafast water–protein interactions

2016 ◽  
Vol 113 (30) ◽  
pp. 8424-8429 ◽  
Author(s):  
Yangzhong Qin ◽  
Lijuan Wang ◽  
Dongping Zhong
Keyword(s):  
Protein Interactions ◽  
Hydration Shell ◽  
Water Dynamics ◽  
Side Chain ◽  
Water Molecules ◽  
Ultrafast Dynamics ◽  
Hydration Water ◽  
Water Side ◽  
Dynamics And Function ◽  
And Function

Protein hydration is essential to its structure, dynamics, and function, but water–protein interactions have not been directly observed in real time at physiological temperature to our awareness. By using a tryptophan scan with femtosecond spectroscopy, we simultaneously measured the hydration water dynamics and protein side-chain motions with temperature dependence. We observed the heterogeneous hydration dynamics around the global protein surface with two types of coupled motions, collective water/side-chain reorientation in a few picoseconds and cooperative water/side-chain restructuring in tens of picoseconds. The ultrafast dynamics in hundreds of femtoseconds is from the outer-layer, bulk-type mobile water molecules in the hydration shell. We also found that the hydration water dynamics are always faster than protein side-chain relaxations but with the same energy barriers, indicating hydration shell fluctuations driving protein side-chain motions on the picosecond time scales and thus elucidating their ultimate relationship.

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