Proprioceptive sensitivity to imposed finger deflections

2022 ◽  
Author(s):  
Katie H Long ◽  
Kristine R McLellan ◽  
Maria Boyarinova ◽  
Sliman J Bensmaia
Keyword(s):  
Joint Angle ◽  
Index Finger ◽  
Human Subjects ◽  
Hand Function ◽  
Sensory Modality ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Vibratory Stimulus ◽  
Proprioceptive Sensitivity

Hand proprioception - the sense of the posture and movements of the wrist and digits - is critical to dexterous manual behavior and to stereognosis, the ability to sense the three-dimensional structure of objects held in the hand. To better understand this sensory modality and its role in hand function, we sought to characterize the acuity with which the postures and movements of finger joints are sensed. To this end, we measured the ability of human subjects to discriminate changes in posture and speed around the three joints of the index finger. In these experiments, we isolated the sensory component by imposing the postures on an otherwise still hand, to complement other studies, in which subjects made judgments on actively achieved postures. We found that subjects could reliably sense 12-16% changes in joint angle and 18-32% changes in joint speed. Furthermore, the acuity for posture and speed was comparable across the three joints of the finger. Finally, task performance was unaffected by the presence of a vibratory stimulus, calling into question the role of cutaneous cues in hand proprioception.

scholarly journals Analysis of structural similarities between brain Thy-1 antigen and immunoglobulin domains. Evidence for an evolutionary relationship and a hypothesis for its functional significance

1981 ◽  
Vol 195 (1) ◽  
pp. 31-40 ◽  
Author(s):  
F E Cohen ◽  
J Novotný ◽  
M J E Sternberg ◽  
D G Campbell ◽  
A F Williams
Keyword(s):  
Functional Significance ◽  
Structure Prediction ◽  
Secondary Structure Prediction ◽  
Three Dimensional ◽  
Evolutionary Relationship ◽  
Dimensional Structure ◽  
Sequence Homologies ◽  
Beta Structure ◽  
Beta 2 Microglobulin

The Thy-1 membrane glycoprotein from rat brain is shown to have structural and sequence homologies with immunoglobulin (Ig) domains on the basis of the following evidence. 1. The two disulphide bonds of Thy-1 are both consistent with the Ig-fold. 2. The molecule contains extensive beta-structure as shown by the c.d. spectrum. 3. Secondary structure prediction locates beta-strands along the sequence in a manner consistent with the Ig-fold. 4. On the basis of rules derived from known beta-sheet structures, a three-dimensional structure with the Ig-fold is predicted as favourable for Thy-1. 5. Sequences in the proposed beta-strands of Thy-1 and known beta-strands of Ig domains show significant sequence homology. This homology is statistically more significant than for the comparison of proposed beta-strand sequences of beta 2-microglobulin with Ig domains. An hypothesis is presented for the possible functional significance of an evolutionary relationship between Thy-1 and Ig. It is suggested that both Thy-1 and Ig evolved from primitive molecules, with an Ig fold, which mediated cell--cell interactions. The present-day role of Thy-1 may be similar to that of the primitive domain.

3D Structure of Striations in the North Pacific

2021 ◽  
Author(s):  
YU ZHANG ◽  
YU PING GUAN ◽  
RUI XIN HUANG
Keyword(s):  
North Pacific ◽  
3D Structure ◽  
Three Dimensional ◽  
Vertical Plane ◽  
Dimensional Structure ◽  
The North ◽  
Layer Analysis ◽  
Fluid Potential ◽  
The North Pacific

AbstractOcean striations are composed of alternating quasi-zonal band-like flows; this kind of organized structure of currents be found in all world’s oceans and seas. Previous studies have mainly been focused on the mechanisms of their generation and propagation. This study uses the spatial high-pass filtering to obtain the three-dimensional structure of ocean striations in the North Pacific in both the z-coordinate and σ-coordinate based on 10-yr averaged SODA3 data. First, we identify an ideal-fluid potential density domain where the striations are undisturbed by the surface forcing and boundary effects. Second, using the isopycnal layer analysis, we show that on isopycnal surfaces the orientations of striations nearly follow the potential vorticity (PV) contours, while in the meridional-vertical plane the central positions of striations are generally aligned with the latitude of zero gradient of the relative PV. Our analysis provides a simple dynamical interpretation and better understanding for the role of ocean striations.

scholarly journals The three-dimensional structure of a class-Pi glutathione S-transferase complexed with glutathione: the active-site hydration provides insights into the reaction mechanism

1998 ◽  
Vol 333 (3) ◽  
pp. 811-816 ◽  
Author(s):  
Antonio PÁRRAGA ◽  
Isabel GARCÍA-SÁEZ ◽  
Sinead B. WALSH ◽  
Timothy J. MANTLE ◽  
Miquel COLL
Keyword(s):  
Conformational Changes ◽  
Active Site ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Water Molecules ◽  
X Ray Diffraction ◽  
Glutathione S Transferase ◽  
X Ray ◽  
The Right

The structure of mouse liver glutathione S-transferase P1-1 complexed with its substrate glutathione (GSH) has been determined by X-ray diffraction analysis. No conformational changes in the glutathione moiety or in the protein, other than small adjustments of some side chains, are observed when compared with glutathione adduct complexes. Our structure confirms that the role of Tyr-7 is to stabilize the thiolate by hydrogen bonding and to position it in the right orientation. A comparison of the enzyme–GSH structure reported here with previously described structures reveals rearrangements in a well-defined network of water molecules in the active site. One of these water molecules (W0), identified in the unliganded enzyme (carboxymethylated at Cys-47), is displaced by the binding of GSH, and a further water molecule (W4) is displaced following the binding of the electrophilic substrate and the formation of the glutathione conjugate. The possibility that one of these water molecules participates in the proton abstraction from the glutathione thiol is discussed.

Role of LHCII-containing macrodomains in the structure, function and dynamics of grana

2000 ◽  
Vol 27 (3) ◽  
pp. 279 ◽  
Author(s):  
G. Garab ◽  
L. Mustárdy
Keyword(s):  
Excitation Energy ◽  
Long Range ◽  
Structural Changes ◽  
Higher Plants ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Lateral Heterogeneity ◽  
Long Distance ◽  
3D Network

In higher plants and green algae two types of thylakoids are distinguished, granum (stacked) and stroma (unstacked) thylakoids. They form a three-dimensional (3D) network with large lateral heterogeneity: photosystem II (PSII) and the associated main chlorophyll a/b light-harvesting complex (LHCII) are found predominantly in the stacked region, while PSI and LHCI are located mainly in the unstacked region of the membrane. This picture emerged from the discovery of the physical separation of the two photosystems (Boardman and Anderson 1964). Granal chloroplasts possess significant flexibility, which is essential for optimizing the photosynthetic machinery under various environmental conditions. However, our understanding concerning the assembly, structural dynamics and regulatory functions of grana is far from being complete. In this paper we overview the significance of the three-dimensional structure of grana in the absorption properties, ionic equilibrations, and in the diffusion of membrane components between the stacked and unstacked regions. Further, we discuss the role of chiral macrodomains in the grana. Lateral heterogeneity of thylakoid membranes is proposed to be a consequence of the formation of macrodomains constituted of LHCII and PSII; their long range order permits long distance migration of excitation energy, which explains the energetic connectivity of PSII particles. The ability of macrodomains to undergo light-induced reversible structural changes lends structural flexibility to the granum. In purified LHCII, which has also been shown to form stacked lamellar aggregates with long range chiral order, excitation energy migrates for large distances; these macroaggregates are also capable of undergoing light-induced reversible structural changes and fluorescence quenching. Hence, some basic properties of grana appear to originate from its main constituent, the LHCII.

scholarly journals Role of Computational Methods in Going beyond X-ray Crystallography to Explore Protein Structure and Dynamics

2018 ◽  
Vol 19 (11) ◽  
pp. 3401 ◽  
Author(s):  
Ashutosh Srivastava ◽  
Tetsuro Nagai ◽  
Arpita Srivastava ◽  
Osamu Miyashita ◽  
Florence Tama
Keyword(s):  
Protein Dynamics ◽  
Computational Methods ◽  
Protein Structures ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
X Ray ◽  
X Ray Crystallography ◽  
Insight Into

Protein structural biology came a long way since the determination of the first three-dimensional structure of myoglobin about six decades ago. Across this period, X-ray crystallography was the most important experimental method for gaining atomic-resolution insight into protein structures. However, as the role of dynamics gained importance in the function of proteins, the limitations of X-ray crystallography in not being able to capture dynamics came to the forefront. Computational methods proved to be immensely successful in understanding protein dynamics in solution, and they continue to improve in terms of both the scale and the types of systems that can be studied. In this review, we briefly discuss the limitations of X-ray crystallography in studying protein dynamics, and then provide an overview of different computational methods that are instrumental in understanding the dynamics of proteins and biomacromolecular complexes.

scholarly journals Solution structure of the strawberry allergen Fra a 1

2012 ◽  
Vol 32 (6) ◽  
pp. 567-575 ◽  
Author(s):  
Christian Seutter von Loetzen ◽  
Kristian Schweimer ◽  
Wilfried Schwab ◽  
Paul Rösch ◽  
Olivia Hartl-Spiegelhauer
Keyword(s):  
Solution Structure ◽  
Three Dimensional ◽  
Protein Family ◽  
Dimensional Structure ◽  
Hydrophobic Pocket ◽  
Pigment Synthesis ◽  
Family Protein ◽  
Pr10 Protein ◽  
Α Helix

The PR10 family protein Fra a 1E from strawberry (Fragaria x ananassa) is down-regulated in white strawberry mutants, and transient RNAi (RNA interference)-mediated silencing experiments confirmed that Fra a 1 is involved in fruit pigment synthesis. In the present study, we determined the solution structure of Fra a 1E. The protein fold is identical with that of other members of the PR10 protein family and consists of a seven-stranded antiparallel β-sheet, two short V-shaped α-helices and a long C-terminal α-helix that encompass a hydrophobic pocket. Whereas Fra a 1E contains the glycine-rich loop that is highly conserved throughout the protein family, the volume of the hydrophobic pocket and the size of its entrance are much larger than expected. The three-dimensional structure may shed some light on its physiological function and may help to further understand the role of PR10 proteins in plants.

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