scholarly journals The final steps of [FeFe]-hydrogenase maturation

2019 ◽  
Vol 116 (32) ◽  
pp. 15802-15810 ◽  
Author(s):  
Oliver Lampret ◽  
Julian Esselborn ◽  
Rieke Haas ◽  
Andreas Rutz ◽  
Rosalind L. Booth ◽  
...  
Keyword(s):  
Functional Integration ◽  
Structural Features ◽  
Site Directed Mutagenesis ◽  
Structural Reorganization ◽  
Biologically Inspired ◽  
Hydrogenase Maturation ◽  
Flexible Loop ◽  
Loop Region ◽  
Shed Light ◽  
Secondary Ligand

The active site (H-cluster) of [FeFe]-hydrogenases is a blueprint for the design of a biologically inspired H2-producing catalyst. The maturation process describes the preassembly and uptake of the unique [2FeH] cluster into apo-hydrogenase, which is to date not fully understood. In this study, we targeted individual amino acids by site-directed mutagenesis in the [FeFe]-hydrogenase CpI of Clostridium pasteurianum to reveal the final steps of H-cluster maturation occurring within apo-hydrogenase. We identified putative key positions for cofactor uptake and the subsequent structural reorganization that stabilizes the [2FeH] cofactor in its functional coordination sphere. Our results suggest that functional integration of the negatively charged [2FeH] precursor requires the positive charges and individual structural features of the 2 basic residues of arginine 449 and lysine 358, which mark the entrance and terminus of the maturation channel, respectively. The results obtained for 5 glycine-to-histidine exchange variants within a flexible loop region provide compelling evidence that the glycine residues function as hinge positions in the refolding process, which closes the secondary ligand sphere of the [2FeH] cofactor and the maturation channel. The conserved structural motifs investigated here shed light on the interplay between the secondary ligand sphere and catalytic cofactor.

Expression and Solution NMR Study of Multi-site Phosphomimetic Mutant BCL-2 Protein

2019 ◽  
Vol 26 (6) ◽  
pp. 449-457
Author(s):  
Ting Song ◽  
Keke Cao ◽  
Yu dan Fan ◽  
Zhichao Zhang ◽  
Zong W. Guo ◽  
...  
Keyword(s):  
Structural Change ◽  
Structural Biology ◽  
Quantum Coherence ◽  
Structural Changes ◽  
Solution Nmr ◽  
Flexible Loop ◽  
Loop Region ◽  
Loop Domain ◽  
Nmr Study ◽  
Binding Groove

Background: The significance of multi-site phosphorylation of BCL-2 protein in the flexible loop domain remains controversial, in part due to the lack of structural biology studies of phosphorylated BCL-2. Objective: The purpose of the study is to explore the phosphorylation induced structural changes of BCL-2 protein. Methods: We constructed a phosphomietic mutant BCL-2(62-206) (t69e, s70e and s87e) (EEEBCL- 2-EK (62-206)), in which the BH4 domain and the part of loop region was truncated (residues 2-61) to enable a backbone resonance assignment. The phosphorylation-induced structural change was visualized by overlapping a well dispersed 15N-1H heteronuclear single quantum coherence (HSQC) NMR spectroscopy between EEE-BCL-2-EK (62-206) and BCL-2. Results: The EEE-BCL-2-EK (62-206) protein reproduced the biochemical and cellular activity of the native phosphorylated BCL-2 (pBCL-2), which was distinct from non-phosphorylated BCL-2 (npBCL-2) protein. Some residues in BH3 binding groove occurred chemical shift in the EEEBCL- 2-EK (62-206) spectrum, indicating that the phosphorylation in the loop region induces a structural change of active site. Conclusion: The phosphorylation of BCL-2 induced structural change in BH3 binding groove.

Skin and dry adhesion

2018 ◽  
Author(s):  
Changhyun Pang ◽  
Chanseok Lee ◽  
Hoon Eui Jeong ◽  
Kahp-Yang Suh
Keyword(s):  
Material Properties ◽  
Structural Features ◽  
Mechanical Interlocking ◽  
Multi Scale ◽  
Skin Patch ◽  
Reversible Adhesion ◽  
Dry Adhesion ◽  
Close Observation ◽  
Dry Adhesives ◽  
Shed Light

Close observation of various attachment systems in animal skins has revealed various exquisite multi-scale architectures for essential functions such as locomotion, crawling, mating, and protection from predators. Some of these adhesion systems of geckos and beetles have unique structural features (e.g. high-aspect ratio, tilted angle, and hierarchical nanostructure), resulting in mechanical interlocking mediated by van der Waals forces or liquid secretion (capillary force). In this chapter, we present an overview of recent advances in bio-inspired, artificial dry adhesives, and biomimetics in the context of nanofabrication and material properties. In addition, relevant bio-inspired structural materials, devices (clean transportation device, interlocker, biomedical skin patch, and flexible strain-gauge sensor) and microrobots are briefly introduced, which would shed light on future smart, directional, and reversible adhesion systems.

Neutrophil extracellular traps in feline cardiogenic arterial thrombi: a pilot study

2021 ◽  
pp. 1098612X2110449
Author(s):  
Ronald HL Li ◽  
Nghi Nguyen ◽  
Joshua A Stern ◽  
Laetitia M Duler
Keyword(s):  
Random Fields ◽  
Histone H3 ◽  
Neutrophil Extracellular Traps ◽  
Structural Features ◽  
Proximal Region ◽  
Aortic Bifurcation ◽  
Iliac Arteries ◽  
Descending Aorta ◽  
Extracellular Traps ◽  
Shed Light

Objectives The aim of this study was to investigate the spatial distribution of neutrophil extracellular traps (NETs) in cardiogenic arterial thromboembolism (CATE). Specifically, we aimed to examine the related structural features of NETs in feline arterial thrombi in relation to their arterial locations. Methods Paraffin-embedded aortic bifurcations from nine cats with hypertrophic cardiomyopathy (four with CATE and five without) were deparaffinized, and NETs were identified by immunodetection based on colocalization of cell-free DNA, citrullinated histone H3 and neutrophil elastase. The distribution of NETs in thrombi within the aortic bifurcations and common iliac arteries (CIAs) was compared based on their proximity to the descending aorta (proximal, mid, distal). Ten random fields per section were captured at × 10 and × 20 magnification for each section of the clot and analyzed. Results The distributions of NETs in thrombi within the aortic bifurcation and CIAs were found to differ in relation to their assigned zones (proximal, mid, distal; P = 0.04); NETs were concentrated mostly in the proximal region in the aortic bifurcations (47.56%, interquartile range [IQR] 14.07–77.95) and CIAs (44.69%, IQR 24.65–85.28), compared with the distal regions (2.69%, IQR 0.10–50.04 [P = 0.027]; 7.08%, IQR 1.27–59.33 [P = 0.02]). Conclusions and relevance The variation in NET distribution within arterial thrombi may shed light on the pathogenesis of thrombus growth. This may be due to possible neutrophil entrapment or variations in shear stress.

scholarly journals Distinct sites for myotoxic and membrane-damaging activities in the C-terminal region of a Lys49-phospholipase A2

2002 ◽  
Vol 366 (3) ◽  
pp. 971-976 ◽  
Author(s):  
Lucimara CHIOATO ◽  
Arthur H.C. de OLIVEIRA ◽  
Roberto RULLER ◽  
Juliana M. SÁ ◽  
Richard J. WARD
Keyword(s):  
Phospholipase A2 ◽  
Lipid Membrane ◽  
Terminal Region ◽  
Site Directed Mutagenesis ◽  
Phospholipid Bilayer ◽  
Directed Mutagenesis ◽  
Aromatic Residues ◽  
Loop Region ◽  
Terminal Loop ◽  
Arginine Residues

Bothropstoxin-I (BthTx-I) is a Lys49-phospholipase A2 from the venom of Bothrops jararacussu which demonstrates both myotoxic and Ca2+-independent membrane-damaging activities. The structural determinants of these activities are poorly defined, therefore site-directed mutagenesis has been used to substitute all cationic and aromatic residues between positions 115 and 129 in the C-terminal loop region of the protein. Substitution of lysine and arginine residues with alanine in the region 117—122 resulted in a significant reduction of myotoxic activity of the recombinant BthTx-I. With the exception of Lys122, these same substitutions did not significantly alter the Ca2+-independent membrane-damaging activity. In contrast, substitution of the positively-charged residues at positions 115, 116 and 122 resulted in reduced Ca2+-independent membrane-damaging activity but, with the exception of Lys122, had no effect on myotoxicity. These results indicate that the two activities are independent and are determined by discrete yet partially overlapping motifs in the C-terminal loop. Results from site-directed mutagenesis of the aromatic residues in the same part of the protein suggest that a region including residues 115—119 interacts superficially with the membrane interface and that the residues around position 125 partially insert into the lipid membrane. These results represent the first detailed mapping of a myotoxic site in a phospholipase A2, and support a model of a Ca2+-independent membrane-damaging mechanism in which the C-terminal region of BthTx-I interacts with and contributes to the perturbation of the phospholipid bilayer.

scholarly journals Atg8-Family Proteins—Structural Features and Molecular Interactions in Autophagy and Beyond

Cells ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 2008 ◽  
Author(s):  
Nicole Wesch ◽  
Vladimir Kirkin ◽  
Vladimir V. Rogov
Keyword(s):  
Protein Interactions ◽  
Membrane Trafficking ◽  
Structural Features ◽  
Structural Level ◽  
Interacting Proteins ◽  
Therapeutic Approaches ◽  
Basic Principles ◽  
Interaction Partners ◽  
Shed Light

Autophagy is a common name for a number of catabolic processes, which keep the cellular homeostasis by removing damaged and dysfunctional intracellular components. Impairment or misbalance of autophagy can lead to various diseases, such as neurodegeneration, infection diseases, and cancer. A central axis of autophagy is formed along the interactions of autophagy modifiers (Atg8-family proteins) with a variety of their cellular counter partners. Besides autophagy, Atg8-proteins participate in many other pathways, among which membrane trafficking and neuronal signaling are the most known. Despite the fact that autophagy modifiers are well-studied, as the small globular proteins show similarity to ubiquitin on a structural level, the mechanism of their interactions are still not completely understood. A thorough analysis and classification of all known mechanisms of Atg8-protein interactions could shed light on their functioning and connect the pathways involving Atg8-proteins. In this review, we present our views of the key features of the Atg8-proteins and describe the basic principles of their recognition and binding by interaction partners. We discuss affinity and selectivity of their interactions as well as provide perspectives for discovery of new Atg8-interacting proteins and therapeutic approaches to tackle major human diseases.

scholarly journals Contribution of the flexible loop region to the function of staphylococcal enterotoxin B

2010 ◽  
Vol 23 (5) ◽  
pp. 415-421 ◽  
Author(s):  
Saeko Yanaka ◽  
Motonori Kudou ◽  
Yoshikazu Tanaka ◽  
Takumi Sasaki ◽  
Sumiyo Takemoto ◽  
...  
Keyword(s):  
Staphylococcal Enterotoxin ◽  
Staphylococcal Enterotoxin B ◽  
Flexible Loop ◽  
Loop Region ◽  
Enterotoxin B
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