scholarly journals Structural Determinants of Coiled Coil Mechanics

2019 ◽  
Author(s):  
Patricia Lopez-Garcia ◽  
Melis Goktas ◽  
Ana E. Bergues-Pupo ◽  
Beate Koksch ◽  
Daniel Varon Silva ◽  
...  
Keyword(s):  
Transition State ◽  
Single Molecule ◽  
Mechanical Stability ◽  
Coiled Coil ◽  
Building Blocks ◽  
Shear Loading ◽  
Hydrophobic Core ◽  
Structural Determinants ◽  
Helix Propensity ◽  
Core Packing

The natural abundance of coiled coil (CC) motifs in the cytoskeleton and the extracellular matrix suggests that CCs play a crucial role in the bidirectional mechanobiochemical signaling between cells and the matrix. Their functional importance and structural simplicity has allowed the development of numerous applications, such as protein-origami structures, drug delivery systems and biomaterials. With the goal of establishing CCs as nanomechanical building blocks, we investigated the importance of helix propensity and hydrophobic core packing on the mechanical stability of 4-heptad CC heterodimers. Using single-molecule force spectroscopy, we show that both parameters determine the force-induced dissociation in shear loading geometry; however, with different effects on the energy landscape. Decreasing the helix propensity lowers the transition barrier height, leading to a concomitant decrease in the distance to the transition state. In contrast, a less tightly packed hydrophobic core increases the distance to the transition state. We propose that this sequence-structure-mechanics relationship is evolutionarily optimized in natural CCs and can be used for tuning their mechanical properties in applications.

scholarly journals Structural determinants of coiled coil mechanics

2019 ◽  
Vol 21 (18) ◽  
pp. 9145-9149 ◽  
Author(s):  
Patricia López-García ◽  
Melis Goktas ◽  
Ana E. Bergues-Pupo ◽  
Beate Koksch ◽  
Daniel Varón Silva ◽  
...  
Keyword(s):  
Packing Density ◽  
Coiled Coil ◽  
Hydrophobic Core ◽  
Sequence Structure ◽  
Structural Determinants ◽  
Helix Propensity ◽  
The Individual ◽  
Relationship Of

In shear geometry, the sequence–structure–mechanics relationship of rationally designed coiled coil heterodimers is determined by the helix propensity of the individual helices and the packing density at the hydrophobic core.

scholarly journals Differential Effects of Hydrophobic Core Packing Residues for Thermodynamic and Mechanical Stability of a Hyperthermophilic Protein

Langmuir ◽  
2016 ◽  
Vol 32 (29) ◽  
pp. 7392-7402 ◽  
Author(s):  
Katarzyna M. Tych ◽  
Matthew Batchelor ◽  
Toni Hoffmann ◽  
Michael C. Wilson ◽  
Megan L. Hughes ◽  
...  
Keyword(s):  
Mechanical Stability ◽  
Hydrophobic Core ◽  
Differential Effects ◽  
Core Packing ◽  
Hyperthermophilic Protein

Hydrophobic core packing in the SH3 domain folding transition state

2002 ◽  
Vol 9 (2) ◽  
pp. 126-130 ◽  
Author(s):  
Julian G.B. Northey ◽  
Ariel A. Di Nardo ◽  
Alan R. Davidson
Keyword(s):  
Transition State ◽  
Sh3 Domain ◽  
Hydrophobic Core ◽  
Core Packing

scholarly journals Single molecule mechanics of the kinesin neck

2009 ◽  
Vol 106 (17) ◽  
pp. 6992-6997 ◽  
Author(s):  
Thomas Bornschlögl ◽  
Günther Woehlke ◽  
Matthias Rief
Keyword(s):  
Single Molecule ◽  
Leucine Zipper ◽  
Structural Integrity ◽  
Mechanical Stability ◽  
Molecular Motor ◽  
Coiled Coil ◽  
Force Microscopy ◽  
Atomic Force ◽  
Kinetics Of ◽  
High Mechanical Stability

Structural integrity as well as mechanical stability of the parts of a molecular motor are crucial for its function. In this study, we used high-resolution force spectroscopy by atomic force microscopy to investigate the force-dependent opening kinetics of the neck coiled coil of Kinesin-1 from Drosophila melanogaster. We find that even though the overall thermodynamic stability of the neck is low, the average opening force of the coiled coil is >11 pN when stretched with pulling velocities >150 nm/s. These high unzipping forces ensure structural integrity during motor motion. The high mechanical stability is achieved through a very narrow N-terminal unfolding barrier if compared with a conventional leucine zipper. The experimentally mapped mechanical unzipping profile allows direct assignment of distinct mechanical stabilities to the different coiled-coil subunits. The coiled-coil sequence seems to be tuned in an optimal way to ensure both mechanical stability as well as motor regulation through charged residues.

Mechanically-Tunable Quantum Interference in Ferrocene-Based Single-Molecule Junctions

2020 ◽  
Author(s):  
María Camarasa-Gómez ◽  
Daniel Hernangómez-Pérez ◽  
Michael S. Inkpen ◽  
Giacomo Lovat ◽  
E-Dean Fung ◽  
...  
Keyword(s):  
Single Molecule ◽  
Quantum Interference ◽  
Degrees Of Freedom ◽  
Building Blocks ◽  
Ferrocene Derivative ◽  
Single Molecule Junctions ◽  
Molecule Junction ◽  
Single Molecule Junction ◽  
The Impact ◽  
D Orbitals

Ferrocenes are ubiquitous organometallic building blocks that comprise a Fe atom sandwiched between two cyclopentadienyl (Cp) rings that rotate freely at room temperature. Of widespread interest in fundamental studies and real-world applications, they have also attracted<br>some interest as functional elements of molecular-scale devices. Here we investigate the impact of<br>the configurational degrees of freedom of a ferrocene derivative on its single-molecule junction<br>conductance. Measurements indicate that the conductance of the ferrocene derivative, which is<br>suppressed by two orders of magnitude as compared to a fully conjugated analog, can be modulated<br>by altering the junction configuration. Ab initio transport calculations show that the low conductance is a consequence of destructive quantum interference effects that arise from the hybridization of metal-based d-orbitals and the ligand-based π-system. By rotating the Cp rings, the hybridization, and thus the quantum interference, can be mechanically controlled, resulting in a conductance modulation that is seen experimentally.<br>

scholarly journals Integrated Optical Phased Arrays for Beam Forming and Steering

2021 ◽  
Vol 11 (9) ◽  
pp. 4017
Author(s):  
Yongjun Guo ◽  
Yuhao Guo ◽  
Chunshu Li ◽  
Hao Zhang ◽  
Xiaoyan Zhou ◽  
...  
Keyword(s):  
Near Infrared ◽  
Phased Arrays ◽  
Mechanical Stability ◽  
Building Blocks ◽  
High Yield ◽  
Beam Forming ◽  
Integrated Optical ◽  
Optical Phased Arrays ◽  
Infrared Spectral ◽  
Spectral Ranges

Integrated optical phased arrays can be used for beam shaping and steering with a small footprint, lightweight, high mechanical stability, low price, and high-yield, benefiting from the mature CMOS-compatible fabrication. This paper reviews the development of integrated optical phased arrays in recent years. The principles, building blocks, and configurations of integrated optical phased arrays for beam forming and steering are presented. Various material platforms can be used to build integrated optical phased arrays, e.g., silicon photonics platforms, III/V platforms, and III–V/silicon hybrid platforms. Integrated optical phased arrays can be implemented in the visible, near-infrared, and mid-infrared spectral ranges. The main performance parameters, such as field of view, beamwidth, sidelobe suppression, modulation speed, power consumption, scalability, and so on, are discussed in detail. Some of the typical applications of integrated optical phased arrays, such as free-space communication, light detection and ranging, imaging, and biological sensing, are shown, with future perspectives provided at the end.

Origin of the Surprising Mechanical Stability of Kinesin’s Neck Coiled Coil

2021 ◽  
Vol 17 (2) ◽  
pp. 1017-1029
Author(s):  
Shu-Xia Liu ◽  
Gang Lü ◽  
Hui Zhang ◽  
Yi-Zhao Geng ◽  
Qing Ji
Keyword(s):  
Mechanical Stability ◽  
Coiled Coil

Assessment of Mechanical Stability of a Parallel Wire Bone Transport System for use with an Ilizarov Frame

1995 ◽  
Vol 209 (3) ◽  
pp. 197-202 ◽  
Author(s):  
R A Wilkes ◽  
A Harrison ◽  
R M Atkins
Keyword(s):  
Soft Tissue ◽  
Transport System ◽  
Mechanical Stability ◽  
Bone Transport ◽  
Shear Loading ◽  
Basic Form ◽  
Parallel Wire ◽  
Fine Wire ◽  
Ilizarov Frame

A novel fine wire bone transport system for use with Ilizarov frames has been used in Bristol. It uses parallel wires instead of crossed wires. Its stiffness has been tested and compared with a crossed wire construct. In its basic form it is not as stiff to bending and shear loading, however, by modification it can be made at least as stiff. A parallel wire construct does not transfix as much soft tissue as a crossed wire construct when used in the leg. This is advantageous, because soft tissue transfixion causes pain and limb swelling, which impair patient mobilization.

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