An Extended Fano–DeVoe Polarizability Theory Similar to the Bayley–Nielsen–Schellman Secular Matrix Method: CD Calculations of Polypeptides Havingα-Helix,β-Sheet, andβ-Turn Structures

The article analyzes the tourism industry and its development in view of the various classification types of tourism. Comparative characteristics of tax revenues in the budget of the Republic of Crimea. The model of competitiveness of tourist field. Calculated the competitiveness of enterprises of the tourism sector matrix method.

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Scorpion toxin-potassium channel interaction law and its applications.

Venoms and Toxins ◽

10.2174/2666121701999200531143349 ◽

2020 ◽

Vol 01 ◽

Author(s):

Zheng Zuo ◽

Zongyun Chen ◽

Zhijian Cao ◽

Wenxin Li ◽

Yingliang Wu

Keyword(s):

Potassium Channel ◽

Scorpion Toxin ◽

Scorpion Toxins ◽

Toxin Binding ◽

Channel Interaction ◽

Binding Interface ◽

Α Helix ◽

Interaction Law ◽

Binding Interfaces ◽

Β Sheet

: The scorpion toxins are the largest potassium channel-blocking peptide family. The understanding of toxin binding interfaces is usually restricted by two classical binding interfaces: one is the toxin α-helix motif, the other is the antiparallel β-sheet motif. In this review, such traditional knowledge was updated by another two different binding interfaces: one is BmKTX toxin using the turn motif between the α-helix and antiparallel β-sheet domains as the binding interface, the other is Ts toxin using turn motif between the β-sheet in the N-terminal and α-helix domains as the binding interface. Their interaction analysis indicated that the scarce negatively charged residues in the scorpion toxins played a critical role in orientating the toxin binding interface. In view of the toxin negatively charged amino acids as “binding interface regulator”, the law of scorpion toxin-potassium channel interaction was proposed, that is, the polymorphism of negatively charged residue distribution determines the diversity of toxin binding interfaces. Such law was used to develop scorpion toxin-potassium channel recognition control technique. According to this technique, three Kv1.3 channel-targeted peptides, using BmKTX as the template, were designed with the distinct binding interfaces from that of BmKTX through modulating the distribution of toxin negatively charged residues. In view of the potassium channel as the common targets of different animal toxins, the proposed law was also shown to helpfully orientate the binding interfaces of other animal toxins. Clearly, the toxin-potassium channel interaction law would strongly accelerate the research and development of different potassium channelblocking animal toxins in the future.

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Insight into the HIV-1 Vif SOCS-box–ElonginBC interaction

Open Biology ◽

10.1098/rsob.130100 ◽

2013 ◽

Vol 3 (11) ◽

pp. 130100 ◽

Cited By ~ 7

Author(s):

Zhisheng Lu ◽

Julien R. C. Bergeron ◽

R. Andrew Atkinson ◽

Torsten Schaller ◽

Dennis A. Veselkov ◽

...

Keyword(s):

Solution Structure ◽

Hydrophobic Interactions ◽

Dynamic Information ◽

Ubiquitin Ligase Complex ◽

Biophysical Studies ◽

Viral Infectivity Factor ◽

Β Sheet ◽

Socs Box ◽

Insight Into ◽

Hiv 1

The HIV-1 viral infectivity factor (Vif) neutralizes cell-encoded antiviral APOBEC3 proteins by recruiting a cellular ElonginB (EloB)/ElonginC (EloC)/Cullin5-containing ubiquitin ligase complex, resulting in APOBEC3 ubiquitination and proteolysis. The suppressors-of-cytokine-signalling-like domain (SOCS-box) of HIV-1 Vif is essential for E3 ligase engagement, and contains a BC box as well as an unusual proline-rich motif. Here, we report the NMR solution structure of the Vif SOCS–ElonginBC (EloBC) complex. In contrast to SOCS-boxes described in other proteins, the HIV-1 Vif SOCS-box contains only one α-helical domain followed by a β-sheet fold. The SOCS-box of Vif binds primarily to EloC by hydrophobic interactions. The functionally essential proline-rich motif mediates a direct but weak interaction with residues 101–104 of EloB, inducing a conformational change from an unstructured state to a structured state. The structure of the complex and biophysical studies provide detailed insight into the function of Vif's proline-rich motif and reveal novel dynamic information on the Vif–EloBC interaction.

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Crystal structures of non-oxidative decarboxylases reveal a new mechanism of action with a catalytic dyad and structural twists

Scientific Reports ◽

10.1038/s41598-021-82660-z ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Matthias Zeug ◽

Nebojsa Markovic ◽

Cristina V. Iancu ◽

Joanna Tripp ◽

Mislav Oreb ◽

...

Keyword(s):

Crystal Structures ◽

Active Site ◽

Enzyme Engineering ◽

Base Catalysis ◽

Oxidative Decarboxylation ◽

Transition State Stabilization ◽

Major Bottleneck ◽

Hydroxybenzoic Acids ◽

Potassium Binding ◽

Β Sheet

AbstractHydroxybenzoic acids, like gallic acid and protocatechuic acid, are highly abundant natural compounds. In biotechnology, they serve as critical precursors for various molecules in heterologous production pathways, but a major bottleneck is these acids’ non-oxidative decarboxylation to hydroxybenzenes. Optimizing this step by pathway and enzyme engineering is tedious, partly because of the complicating cofactor dependencies of the commonly used prFMN-dependent decarboxylases. Here, we report the crystal structures (1.5–1.9 Å) of two homologous fungal decarboxylases, AGDC1 from Arxula adenivorans, and PPP2 from Madurella mycetomatis. Remarkably, both decarboxylases are cofactor independent and are superior to prFMN-dependent decarboxylases when heterologously expressed in Saccharomyces cerevisiae. The organization of their active site, together with mutational studies, suggests a novel decarboxylation mechanism that combines acid–base catalysis and transition state stabilization. Both enzymes are trimers, with a central potassium binding site. In each monomer, potassium introduces a local twist in a β-sheet close to the active site, which primes the critical H86-D40 dyad for catalysis. A conserved pair of tryptophans, W35 and W61, acts like a clamp that destabilizes the substrate by twisting its carboxyl group relative to the phenol moiety. These findings reveal AGDC1 and PPP2 as founding members of a so far overlooked group of cofactor independent decarboxylases and suggest strategies to engineer their unique chemistry for a wide variety of biotechnological applications.

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