scholarly journals Production of a Human Histamine Receptor for NMR Spectroscopy in Aqueous Solutions

Biomolecules ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 632
Author(s):  
Emma Mulry ◽  
Arka Prabha Ray ◽  
Matthew T. Eddy

G protein-coupled receptors (GPCRs) bind a broad array of extracellular molecules and transmit intracellular signals that initiate physiological responses. The signal transduction functions of GPCRs are inherently related to their structural plasticity, which can be experimentally observed by spectroscopic techniques. Nuclear magnetic resonance (NMR) spectroscopy in particular is an especially advantageous method to study the dynamic behavior of GPCRs. The success of NMR studies critically relies on the production of functional GPCRs containing stable-isotope labeled probes, which remains a challenging endeavor for most human GPCRs. We report a protocol for the production of the human histamine H1 receptor (H1R) in the methylotrophic yeast Pichia pastoris for NMR experiments. Systematic evaluation of multiple expression parameters resulted in a ten-fold increase in the yield of expressed H1R over initial efforts in defined media. The expressed receptor could be purified to homogeneity and was found to respond to the addition of known H1R ligands. Two-dimensional transverse relaxation-optimized spectroscopy (TROSY) NMR spectra of stable-isotope labeled H1R show well-dispersed and resolved signals consistent with a properly folded protein, and 19F-NMR data register a response of the protein to differences in efficacies of bound ligands.

2018 ◽  
Vol 69 (7) ◽  
pp. 1838-1841
Author(s):  
Hajnal Kelemen ◽  
Angella Csillag ◽  
Bela Noszal ◽  
Gabor Orgovan

Ezetimibe, the antihyperlipidemic drug of poor bioavailability was complexed with native and derivatized cyclodextrins.The complexes were characterized in terms stability, stoichiometry and structure using various 1D and 2D solution NMR spectroscopic techniques. The complexes were found to be of moderate stability (logK[3). The least stable inclusion complex is formed with b-cyclodextrin, while the ezetimibe-methylated-b--cyclodextrin has a 7-fold higher stability. The results can be useful to improve the poor water-solubility and the concomitant bioavailability of ezetimibe.


2020 ◽  
Vol 27 ◽  
Author(s):  
Marian Vincenzi ◽  
Flavia Anna Mercurio ◽  
Marilisa Leone

Background: NMR spectroscopy is one of the most powerful tools to study the structure and interaction properties of peptides and proteins from a dynamic perspective. Knowing the bioactive conformations of peptides is crucial in the drug discovery field to design more efficient analogue ligands and inhibitors of protein-protein interactions targeting therapeutically relevant systems. Objective: This review provides a toolkit to investigate peptide conformational properties by NMR. Methods: Articles cited herein, related to NMR studies of peptides and proteins were mainly searched through Pubmed and the web. More recent and old books on NMR spectroscopy written by eminent scientists in the field were consulted as well. Results: The review is mainly focused on NMR tools to gain the 3D structure of small unlabeled peptides. It is more application-oriented as it is beyond its goal to deliver a profound theoretical background. However, the basic principles of 2D homonuclear and heteronuclear experiments are briefly described. Protocols to obtain isotopically labeled peptides and principal triple resonance experiments needed to study them, are discussed as well. Conclusion: NMR is a leading technique in the study of conformational preferences of small flexible peptides whose structure can be often only described by an ensemble of conformations. Although NMR studies of peptides can be easily and fast performed by canonical protocols established a few decades ago, more recently we have assisted to tremendous improvements of NMR spectroscopy to investigate instead large systems and overcome its molecular weight limit.


2020 ◽  
Vol 295 (8) ◽  
pp. 2483-2494
Author(s):  
Hiroyuki Yoshida ◽  
Mika Aoki ◽  
Aya Komiya ◽  
Yoko Endo ◽  
Keigo Kawabata ◽  
...  

The immune-regulatory compound histamine is involved in the metabolism of the essential skin component hyaluronan (HA). We previously reported that histamine up-regulates the expression of HYBID (hyaluronan-binding protein involved in hyaluronan depolymerization, also called CEMIP or KIAA1199), which plays a key role in HA degradation. However, no information is available about histamine's effects on HA synthase (HAS) expression, the molecular sizes of HA species produced, and histamine receptors and their signaling pathways in skin fibroblasts. Moreover, histamine's effects on photoaged skin remain elusive. Here, we show that histamine increases HA degradation by up-regulating HYBID and down-regulating HAS2 in human skin fibroblasts in a dose- and time-dependent manner and thereby decreases the total amounts and sizes of newly produced HA. Histamine H1 blocker abrogated the histamine effects on HYBID up-regulation, HAS2 suppression, and HA degradation. Histamine H1 agonist exhibited effects on HA levels, composition, and breakdown similar to those of histamine. Of note, blockade of protein kinase Cδ or PI3K–Akt signaling abolished histamine-mediated HYBID stimulation and HAS2 suppression, respectively. Immunohistochemical experiments revealed a significant ∼2-fold increase in tryptase-positive mast cells in photoaged skin, where HYBID and HAS2 expression levels were increased and decreased, respectively, compared with photoprotected skin. These results indicate that histamine controls HA metabolism by up-regulating HYBID and down-regulating HAS2 via distinct signaling pathways downstream of histamine receptor H1. They further suggest that histamine may contribute to photoaged skin damage by skewing HA metabolism toward degradation.


Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 4089
Author(s):  
Katarzyna Betlejewska-Kielak ◽  
Elżbieta Bednarek ◽  
Armand Budzianowski ◽  
Katarzyna Michalska ◽  
Jan K. Maurin

Racemic ketoprofen (KP) and β-cyclodextrin (β-CD) powder samples from co-precipitation (1), evaporation (2), and heating-under-reflux (3) were analysed using X-ray techniques and nuclear magnetic resonance (NMR) spectroscopy. On the basis of NMR studies carried out in an aqueous solution, it was found that in the samples obtained by methods 1 and 2, there were large excesses of β-CD in relation to KP, 10 and 75 times, respectively, while the sample obtained by method 3 contained equimolar amounts of β-CD and KP. NMR results indicated that KP/β-CD inclusion complexes were formed and the estimated binding constants were approximately 2400 M−1, showing that KP is quite strongly associated with β-CD. On the other hand, the X-ray single-crystal technique in the solid state revealed that the (S)-KP/β-CD inclusion complex with a stoichiometry of 2:2 was obtained as a result of heating-under-reflux, for which the crystal and molecular structure were examined. Among the methods used for the preparation of the KP/β-CD complex, only method 3 is suitable.


Author(s):  
Lisa Klug ◽  
Pablo Tarazona ◽  
Clemens Gruber ◽  
Karlheinz Grillitsch ◽  
Brigitte Gasser ◽  
...  

Molecules ◽  
2021 ◽  
Vol 26 (7) ◽  
pp. 1942
Author(s):  
Ilche Gjuroski ◽  
Julien Furrer ◽  
Martina Vermathen

Porphyrinic compounds are widespread in nature and play key roles in biological processes such as oxygen transport in blood, enzymatic redox reactions or photosynthesis. In addition, both naturally derived as well as synthetic porphyrinic compounds are extensively explored for biomedical and technical applications such as photodynamic therapy (PDT) or photovoltaic systems, respectively. Their unique electronic structures and photophysical properties make this class of compounds so interesting for the multiple functions encountered. It is therefore not surprising that optical methods are typically the prevalent analytical tool applied in characterization and processes involving porphyrinic compounds. However, a wealth of complementary information can be obtained from NMR spectroscopic techniques. Based on the advantage of providing structural and dynamic information with atomic resolution simultaneously, NMR spectroscopy is a powerful method for studying molecular interactions between porphyrinic compounds and macromolecules. Such interactions are of special interest in medical applications of porphyrinic photosensitizers that are mostly combined with macromolecular carrier systems. The macromolecular surrounding typically stabilizes the encapsulated drug and may also modify its physical properties. Moreover, the interaction with macromolecular physiological components needs to be explored to understand and control mechanisms of action and therapeutic efficacy. This review focuses on such non-covalent interactions of porphyrinic drugs with synthetic polymers as well as with biomolecules such as phospholipids or proteins. A brief introduction into various NMR spectroscopic techniques is given including chemical shift perturbation methods, NOE enhancement spectroscopy, relaxation time measurements and diffusion-ordered spectroscopy. How these NMR tools are used to address porphyrin–macromolecule interactions with respect to their function in biomedical applications is the central point of the current review.


Genetics ◽  
1999 ◽  
Vol 151 (4) ◽  
pp. 1379-1391
Author(s):  
Monique A Johnson ◽  
Hans R Waterham ◽  
Galyna P Ksheminska ◽  
Liubov R Fayura ◽  
Joan Lin Cereghino ◽  
...  

Abstract We have developed two novel schemes for the direct selection of peroxisome-biogenesis-defective (pex) mutants of the methylotrophic yeast Pichia pastoris. Both schemes take advantage of our observation that methanol-induced pex mutants contain little or no alcohol oxidase (AOX) activity. AOX is a peroxisomal matrix enzyme that catalyzes the first step in the methanol-utilization pathway. One scheme utilizes allyl alcohol, a compound that is not toxic to cells but is oxidized by AOX to acrolein, a compound that is toxic. Exposure of mutagenized populations of AOX-induced cells to allyl alcohol selectively kills AOX-containing cells. However, pex mutants without AOX are able to grow. The second scheme utilizes a P. pastoris strain that is defective in formaldehyde dehydrogenase (FLD), a methanol pathway enzyme required to metabolize formaldehyde, the product of AOX. AOX-induced cells of fld1 strains are sensitive to methanol because of the accumulation of formaldehyde. However, fld1 pex mutants, with little active AOX, do not efficiently oxidize methanol to formaldehyde and therefore are not sensitive to methanol. Using these selections, new pex mutant alleles in previously identified PEX genes have been isolated along with mutants in three previously unidentified PEX groups.


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