scholarly journals Phosphoserine for the generation of lanthanide binding sites on proteins for paramagnetic NMR

2020 ◽  
Author(s):  
Sreelakshmi Mekkattu Tharayil ◽  
Mithun Chamikara Mahawaththa ◽  
Choy-Theng Loh ◽  
Ibidolapo Adekoya ◽  
Gottfried Otting
Keyword(s):  
Binding Sites ◽  
Structural Information ◽  
Lanthanide Ions ◽  
Paramagnetic Nmr ◽  
Pseudocontact Shifts ◽  
Magnetic Susceptibility Anisotropy ◽  
Lanthanide Ion ◽  
Close Proximity ◽  
Charged Residues

Abstract. Pseudocontact shifts (PCS) generated by paramagnetic lanthanide ions provide valuable long-range structural information in NMR spectroscopic analyses of biological macromolecules such as proteins, but labelling proteins site-specifically with a single lanthanide ion remains an ongoing challenge, especially for proteins that are not suitable for ligation with cysteine-reactive lanthanide complexes. We show that a specific lanthanide binding site can be installed on proteins by incorporation of phosphoserine in conjunction with other negatively charged residues, such as aspartate, glutamate or a second phosphoserine residue. The close proximity of the binding sites to the protein backbone leads to good immobilization of the lanthanide ion, as evidenced by the excellent quality of fits between experimental PCSs and PCSs calculated with a single magnetic susceptibility anisotropy (Δχ) tensor. An improved two-plasmid system was designed to enhance the yields of proteins with genetically encoded phosphoserine and good lanthanide ion affinities were obtained when the side chains of the phosphoserine and aspartate residues are not engaged in salt bridges, although the presence of too many negatively charged residues in close proximity can also lead to unfolding of the protein. In view of the quality of the Δχ tensors that can be obtained from lanthanide binding sites generated by site-specific incorporation of phosphoserine, this method presents an attractive tool for generating PCSs in stable proteins, particularly as it is independent of cysteine residues.

scholarly journals Phosphoserine for the generation of lanthanide-binding sites on proteins for paramagnetic nuclear magnetic resonance spectroscopy

2021 ◽  
Vol 2 (1) ◽  
pp. 1-13
Author(s):  
Sreelakshmi Mekkattu Tharayil ◽  
Mithun Chamikara Mahawaththa ◽  
Choy-Theng Loh ◽  
Ibidolapo Adekoya ◽  
Gottfried Otting
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Binding Sites ◽  
Lanthanide Ions ◽  
Resonance Spectroscopy ◽  
Lanthanide Ion ◽  
Close Proximity ◽  
Charged Residues ◽  
Nuclear Magnetic

Abstract. Pseudocontact shifts (PCSs) generated by paramagnetic lanthanide ions provide valuable long-range structural information in nuclear magnetic resonance (NMR) spectroscopic analyses of biological macromolecules such as proteins, but labelling proteins site-specifically with a single lanthanide ion remains an ongoing challenge, especially for proteins that are not suitable for ligation with cysteine-reactive lanthanide complexes. We show that a specific lanthanide-binding site can be installed on proteins by incorporation of phosphoserine in conjunction with other negatively charged residues, such as aspartate, glutamate or a second phosphoserine residue. The close proximity of the binding sites to the protein backbone leads to good immobilization of the lanthanide ion, as evidenced by the excellent quality of fits between experimental PCSs and PCSs calculated with a single magnetic susceptibility anisotropy (Δχ) tensor. An improved two-plasmid system was designed to enhance the yields of proteins with genetically encoded phosphoserine, and good lanthanide ion affinities were obtained when the side chains of the phosphoserine and aspartate residues are not engaged in salt bridges, although the presence of too many negatively charged residues in close proximity can also lead to unfolding of the protein. In view of the quality of the Δχ tensors that can be obtained from lanthanide-binding sites generated by site-specific incorporation of phosphoserine, this method presents an attractive tool for generating PCSs in stable proteins, particularly as it is independent of cysteine residues.

The Influence Of The Led Luminaires Electrical Parameters On Their Correlated Colour Temperature During Operation Mode

2020 ◽  
pp. 89-96
Author(s):  
Sergei S. Kapitonov ◽  
Alexei S. Vinokurov ◽  
Sergei V. Prytkov ◽  
Sergei Yu. Grigorovich ◽  
Anastasia V. Kapitonova ◽  
...  
Keyword(s):  
Operation Mode ◽  
Light Sources ◽  
Electrical Parameters ◽  
Colour Temperature ◽  
Radiation Spectra ◽  
Service Period ◽  
Close Proximity ◽  
Definition Of ◽  
Comprehensive Study

The article describes the results of comprehensive study aiming at increase of quality of LED luminaires and definition of the nature of changes in their correlated colour temperature (CCT) in the course of operation. Dependences of CCT of LED luminaires with remote and close location of phosphor for 10 thousand hours of operation in different electric modes were obtained; the results of comparison between the initial and final radiation spectra of the luminaires are presented; using mathematical statistics methods, variation of luminaire CCT over the service period claimed by the manufacturer is forecast; the least favourable electric operation modes with the highest CCT variation observed are defined. The obtained results have confirmed availability of the problem of variation of CCT of LED luminaires during their operation. Possible way of its resolution is application of more qualitative and therefore expensive LEDs with close proximity of phosphor or LEDs with remote phosphor. The article may be interesting both for manufacturers and consumers of LED light sources and lighting devices using them.

scholarly journals Addressing Practical Issues Related Tto Nursing Care For International Visitors To Hiroshima

2014 ◽  
Vol 48 (2) ◽  
pp. 299-307 ◽  
Author(s):  
Mariko Nishikawa ◽  
Kiyoka Niiya ◽  
Masako Okayasu
Keyword(s):  
Foreign Language ◽  
Tourist Destinations ◽  
Word Analysis ◽  
Quality Of Patient Care ◽  
Close Proximity ◽  
Open Question ◽  
Japanese Nurses ◽  
Nursing Professionals ◽  
International Visitors

When nine million foreigners visited Japan in 2013, the federal government set a goal to attract an additional two and a half million visitors including medical tourists by 2020. This research investigates the attitudes and concerns of Japanese nurses when they are in a situation dealing with foreign patients. The data were collected from March through September 2010, from 114 nurses at three hospitals, in close proximity to popular tourist destinations in Hiroshima. A questionnaire was developed for this research, named Mari Meter, which included a section to write answers to an open question for the nurses to express their opinions. These responses were examined statistically and by word analysis using Text Mining Studio. Japanese nurses expressed greatest concern about payment options, foreign language skills, and issues of informed consent, when dealing with foreigners. The results confirm that, in order to provide a high quality of patient care, extra preparation and a greater knowledge of international workers and visitors are required by nursing professionals in Japan.


scholarly journals X-rays Image reconstruction using Proximal Algorithm and adapted TV Regularization

2021 ◽  
Vol 348 ◽  
pp. 01011
Author(s):  
Aicha Allag ◽  
Redouane Drai ◽  
Tarek Boutkedjirt ◽  
Abdessalam Benammar ◽  
Wahiba Djerir
Keyword(s):  
Structural Information ◽  
X Rays ◽  
Reconstruction Algorithms ◽  
Reconstruction Problem ◽  
Tv Regularization ◽  
Object Based ◽  
Suggested Technique ◽  
Reconstruction Image ◽  
Ill Posed

Computed tomography (CT) aims to reconstruct an internal distribution of an object based on projection measurements. In the case of a limited number of projections, the reconstruction problem becomes significantly ill-posed. Practically, reconstruction algorithms play a crucial role in overcoming this problem. In the case of missing or incomplete data, and in order to improve the quality of the reconstruction image, the choice of a sparse regularisation by adding l1 norm is needed. The reconstruction problem is then based on using proximal operators. We are interested in the Douglas-Rachford method and employ total variation (TV) regularization. An efficient technique based on these concepts is proposed in this study. The primary goal is to achieve high-quality reconstructed images in terms of PSNR parameter and relative error. The numerical simulation results demonstrate that the suggested technique minimizes noise and artifacts while preserving structural information. The results are encouraging and indicate the effectiveness of the proposed strategy.

scholarly journals Inhibitors of Mycobacterium tuberculosis EgtD target both substrate binding sites to limit hercynine production

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Thanuja D. Sudasinghe ◽  
Michael T. Banco ◽  
Donald R. Ronning
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Binding Sites ◽  
Enzyme Inhibitor ◽  
Structural Information ◽  
Alkylating Agents ◽  
Enzyme Active Site ◽  
Treatment Regimens ◽  
Domains Of Life ◽  
Substrate Binding Sites

AbstractErgothioneine (EGT) is a low molecular weight histidine betaine essential in all domains of life but only synthesized by selected few organisms. Synthesis of EGT by Mycobacterium tuberculosis (M. tb) is critical for maintaining bioenergetic homeostasis and protecting the bacterium from alkylating agents, oxidative stress, and anti-tubercular drugs. EgtD, an S-adenosylmethionine-dependent methyltransferase (AdoMet), catalyzes the trimethylation of L-Histidine to initiate EGT biosynthesis and this reaction has been shown to be essential for EGT production in mycobacteria and for long-term infection of murine macrophages by M. tb. In this work, library screening and structure-guided strategies identified multiple classes of M. tb EgtD inhibitors that bind in various regions of the enzyme active site. X-ray crystal structures of EgtD-inhibitor complexes confirm that L-Histidine analogs bind solely to the L-Histidine binding site while drug-like inhibitors, such as TGX-221, and S-Glycyl-H-1152 span both the L-Histidine and AdoMet binding sites. These enzyme-inhibitor complexes provide detailed structural information of compound scaffolds useful for developing more potent inhibitors that could shorten Tuberculosis treatment regimens by weakening important bacterial defenses.

scholarly journals Chromophore Assignment in C-Phycocyanin from Mastigocladus laminosus

1987 ◽  
Vol 42 (3) ◽  
pp. 258-262 ◽  
Author(s):  
S. Siebzehnrübl ◽  
R. Fischer ◽  
H. Scheer
Keyword(s):  
Circular Dichroism ◽  
Binding Sites ◽  
Specific Binding ◽  
Reactive Site ◽  
Spectral Changes ◽  
Mastigocladus Laminosus ◽  
Specific Binding Sites ◽  
Close Proximity ◽  
Circular Dichroïsm ◽  
Unambiguous Assignment

C-phycocyanin from the cyanobacterium, Mastigocladus laminosus, and its subunits have been treated with ρ-chloromercuribenzenesulfonate (PCMS). A single reactive site was found on the 13- subunit, and assigned to the single free cystein-β109. The concomitant spectral changes (absorp­tion, fluorescence, circular dichroism), together with the known close proximity of cys-β109 to chromophore β82, allowed an unambiguous assignment of the three spectrally, biochemically and functionally different chromophores to specific binding sites on the two peptide chains (α84: 616-618, β82: 622-624, β153: 598-600 nm).

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