scholarly journals The role of conformational entropy in the determination of structural-kinetic relationships for helix-coil transitions

2017 ◽  
Author(s):  
Joseph F. Rudzinski ◽  
Tristan Bereau

Coarse-grained molecular simulation models can provide significant insight into the complex behavior of protein systems, but suffer from an inherently distorted description of dynamical properties. We recently demonstrated that, for a heptapeptide of alanine residues, the structural and kinetic properties of a simulation model are linked in a rather simple way, given a certain level of physics present in the model. In this work, we extend these findings to a longer peptide, for which the representation of configuration space in terms of a full enumeration of sequences of helical/coil states along the peptide backbone is impractical. We verify the structural-kinetic relationships by scanning the parameter space of a simple native-biased model and then employ a distinct transferable model to validate and generalize the conclusions. Our results further demonstrate the validity of the previous findings, while clarifying the role of conformational entropy in the determination of the structural-kinetic relationships. More specifically, while the global, long timescale kinetic properties of a particular class of models with varying energetic parameters but approximately fixed conformational entropy are determined by the overarching structural features of the ensemble, a shift in these kinetic observables occurs for models with a distinct representation of steric interactions. At the same time, the relationship between structure and more local, faster kinetic properties is not affected by varying the conformational entropy of the model.

2021 ◽  
Vol 15 ◽  
Author(s):  
Rushi Zou ◽  
Linling Li ◽  
Li Zhang ◽  
Gan Huang ◽  
Zhen Liang ◽  
...  

Pain sensitivity is highly variable among individuals, and it is clinically important to predict an individual’s pain sensitivity for individualized diagnosis and management of pain. Literature has shown that pain sensitivity is associated with regional structural features of the brain, but it remains unclear whether pain sensitivity is also related to structural brain connectivity. In the present study, we investigated the relationship between pain thresholds and morphological connectivity (MC) inferred from structural MRI based on data of 221 healthy participants. We found that MC was highly predictive of an individual’s pain thresholds and, importantly, it had a better prediction performance than regional structural features. We also identified a number of most predictive MC features and confirmed the crucial role of the prefrontal cortex in the determination of pain sensitivity. These results suggest the potential of using structural MRI-based MC to predict an individual’s pain sensitivity in clinical settings, and hence this study has important implications for diagnosis and treatment of pain.


Author(s):  
D. F. Blake ◽  
L. F. Allard ◽  
D. R. Peacor

Echinodermata is a phylum of marine invertebrates which has been extant since Cambrian time (c.a. 500 m.y. before the present). Modern examples of echinoderms include sea urchins, sea stars, and sea lilies (crinoids). The endoskeletons of echinoderms are composed of plates or ossicles (Fig. 1) which are with few exceptions, porous, single crystals of high-magnesian calcite. Despite their single crystal nature, fracture surfaces do not exhibit the near-perfect {10.4} cleavage characteristic of inorganic calcite. This paradoxical mix of biogenic and inorganic features has prompted much recent work on echinoderm skeletal crystallography. Furthermore, fossil echinoderm hard parts comprise a volumetrically significant portion of some marine limestones sequences. The ultrastructural and microchemical characterization of modern skeletal material should lend insight into: 1). The nature of the biogenic processes involved, for example, the relationship of Mg heterogeneity to morphological and structural features in modern echinoderm material, and 2). The nature of the diagenetic changes undergone by their ancient, fossilized counterparts. In this study, high resolution TEM (HRTEM), high voltage TEM (HVTEM), and STEM microanalysis are used to characterize tha ultrastructural and microchemical composition of skeletal elements of the modern crinoid Neocrinus blakei.


2019 ◽  
Vol 58 (2) ◽  
pp. 249-259
Author(s):  
Joseph Acquisto

This essay examines a polemic between two Baudelaire critics of the 1930s, Jean Cassou and Benjamin Fondane, which centered on the relationship of poetry to progressive politics and metaphysics. I argue that a return to Baudelaire's poetry can yield insight into what seems like an impasse in Cassou and Fondane. Baudelaire provides the possibility of realigning metaphysics and politics so that poetry has the potential to become the space in which we can begin to think the two of them together, as opposed to seeing them in unresolvable tension. Or rather, the tension that Baudelaire animates between the two allows us a new way of thinking about the role of esthetics in moments of political crisis. We can in some ways see Baudelaire as responding, avant la lettre, to two of his early twentieth-century readers who correctly perceived his work as the space that breathes a new urgency into the questions of how modern poetry relates to the world from which it springs and in which it intervenes.


Author(s):  
Miriam Bak McKenna

Abstract Situating itself in current debates over the international legal archive, this article delves into the material and conceptual implications of architecture for international law. To do so I trace the architectural developments of international law’s organizational and administrative spaces during the early to mid twentieth century. These architectural endeavours unfolded in three main stages: the years 1922–1926, during which the International Labour Organization (ILO) building, the first building exclusively designed for an international organization was constructed; the years 1927–1937 which saw the great polemic between modernist and classical architects over the building of the Palace of Nations; and the years 1947–1952, with the triumph of modernism, represented by the UN Headquarters in New York. These events provide an illuminating allegorical insight into the physical manifestation, modes of self-expression, and transformation of international law during this era, particularly the relationship between international law and the function and role of international organizations.


Biomolecules ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1790
Author(s):  
Lei Zhang ◽  
Ruohan Jia ◽  
Huizhen Li ◽  
Huarun Yu ◽  
Keke Ren ◽  
...  

Ferroptosis, a newly described type of iron-dependent programmed cell death that is distinct from apoptosis, necroptosis, and other types of cell death, is involved in lipid peroxidation (LP), reactive oxygen species (ROS) production, and mitochondrial dysfunction. Accumulating evidence has highlighted vital roles for ferroptosis in multiple diseases, including acute kidney injury, cancer, hepatic fibrosis, Parkinson’s disease, and Alzheimer’s disease. Therefore, ferroptosis has become one of the research hotspots for disease treatment and attracted extensive attention in recent years. This review mainly summarizes the relationship between ferroptosis and various diseases classified by the system, including the urinary system, digestive system, respiratory system, nervous system. In addition, the role and molecular mechanism of multiple inhibitors and inducers for ferroptosis are further elucidated. A deeper understanding of the relationship between ferroptosis and multiple diseases may provide new strategies for researching diseases and drug development based on ferroptosis.


2006 ◽  
Vol 290 (6) ◽  
pp. F1295-F1302 ◽  
Author(s):  
Stan F. J. van de Graaf ◽  
Joost G. J. Hoenderop ◽  
René J. M. Bindels

The epithelial Ca2+ channels TRPV5 and TRPV6 are the most Ca2+-selective members of the TRP channel superfamily. These channels are the prime target for hormonal control of the active Ca2+ flux from the urine space or intestinal lumen to the blood compartment. Insight into their regulation is, therefore, pivotal in our understanding of the (patho)physiology of Ca2+ homeostasis. The recent elucidation of TRPV5/6-associated proteins has provided new insight into the molecular mechanisms underlying the regulation of these channels. In this review, we describe the various means of TRPV5/6 regulation, the role of channel-associated proteins herein, and the relationship between both processes.


2014 ◽  
Vol 37 (6) ◽  
pp. E8 ◽  
Author(s):  
Matthew Womeldorff ◽  
David Gillespie ◽  
Randy L. Jensen

Glioblastoma multiforme (GBM) is a highly aggressive brain tumor with an exceptionally poor patient outcome despite aggressive therapy including surgery, radiation, and chemotherapy. This aggressive phenotype may be associated with intratumoral hypoxia, which probably plays a key role in GBM tumor growth, development, and angiogenesis. A key regulator of cellular response to hypoxia is the protein hypoxia-inducible factor–1 (HIF-1). An examination of upstream hypoxic and nonhypoxic regulation of HIF-1 as well as a review of the downstream HIF-1–regulated proteins may provide further insight into the role of this transcription factor in GBM pathophysiology. Recent insights into upstream regulators that intimately interact with HIF-1 could provide potential therapeutic targets for treatment of this tumor. The same is potentially true for HIF-1–mediated pathways of glycolysis-, angiogenesis-, and invasion-promoting proteins. Thus, an understanding of the relationship between HIF-1, its upstream protein regulators, and its downstream transcribed genes in GBM pathogenesis could provide future treatment options for the care of patients with these tumors.


Author(s):  
Pınar Özgökbel Bilis ◽  
Ali Emre Bilis

Television channels for children contain many cartoons and programs. These productions reach the viewers via both the television and the channel's official website. TRT Çocuk, broadcasting for children as a government television channel, presents many locally produced animated cartoons to the viewers. A product of the modern and digital technology, these locally produced cartoons carry importance in terms of transfer of social values. This study focuses on locally produced animation cartoons that have an important potential especially in the transfer of national and moral values. Determination of values conveyed via cartoons that bear importance in the transformation of television into an educational tool allows the media and child relationships to become visible. This work aims to examine the relationship between media and values by defining the concept of “value.” After creating a corporate frame, the study brings to light the social values conveyed in locally produced cartoons aired on TRT Çocuk television channel via qualitative analysis method.


2020 ◽  
Vol 11 ◽  
Author(s):  
Kathleen A. Moore ◽  
Austin Campbell

Abstract Intimate relationships are an integral part of our lives, but the rate of relationship breakups is high. We explored the role of the investment model and the traits that influence investments on relationship satisfaction among 146 volunteers (age M = 28.76 years, SD = 10.23). Relationship satisfaction was predicted by investments, which in turn were predicted by attachment, personality and love style. Clinicians working with individuals or couples with relationship issues may benefit from knowing how invested they are in the relationship and their love style. Insight into imbalances in these constructs between partners may be used to facilitate relationship satisfaction.


Author(s):  
Jaco Beyers

Human consciousness instinctively tries to make sense of reality. Different human interpretations of reality lead to a world consisting of multiple realities. Conflict occurs when differing realities (worldviews) encounter one another. Worldviews are socially created and determine human behaviour and, as such, most often find expression in religion. The discussion of conflict and the role of religion in civil society take place within the discourse of the sociology of religion. Religion is socially determined. Peter Berger’s insight into the sociology of religion therefore plays an important role in establishing the relationship between religion and civil society as one that takes on different forms. Thus, a clear definition of both civil society and religion was needed to understand the nature of these relationships. The role of religion in civil society with regard to the presence of conflict in society was further investigated in this article. The conditions under which conflict in society occurs were discussed, as were the conditions for tolerance in society, for religion ultimately becomes the provider of moral discernment when conflict occurs in civil society.


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