• MeSH
• molekulární biologie MeSH
• proteiny MeSH

• Konspekt
• Biochemie. Molekulární biologie. Biofyzika
• NLK Obory
• biochemie
• biologie

• Klíčová slova
• Biologie molekulární, Proteiny,
• MeSH
• molekulární biologie MeSH
• proteiny MeSH

Ca2+/calmodulin-dependent protein kinase kinase 2 (CaMKK2) regulates several key physiological and pathophysiological processes, and its dysregulation has been implicated in obesity, diabetes, and cancer. CaMKK2 is inhibited through phosphorylation in a process involving binding to the scaffolding 14-3-3 protein, which maintains CaMKK2 in the phosphorylation-mediated inhibited state. The previously reported structure of the N-terminal CaMKK2 14-3-3-binding motif bound to 14-3-3 suggested that the interaction between 14-3-3 and CaMKK2 could be stabilized by small-molecule compounds. Thus, we investigated the stabilization of interactions between CaMKK2 and 14-3-3γ by Fusicoccin A and other fusicoccanes-diterpene glycosides that bind at the interface between the 14-3-3 ligand binding groove and the 14-3-3 binding motif of the client protein. Our data reveal that two of five tested fusicoccanes considerably increase the binding of phosphopeptide representing the 14-3-3 binding motif of CaMKK2 to 14-3-3γ. Crystal structures of two ternary complexes suggest that the steric contacts between the C-terminal part of the CaMKK2 14-3-3 binding motif and the adjacent fusicoccane molecule are responsible for differences in stabilization potency between the study compounds. Moreover, our data also show that fusicoccanes enhance the binding affinity of phosphorylated full-length CaMKK2 to 14-3-3γ, which in turn slows down CaMKK2 dephosphorylation, thus keeping this protein in its phosphorylation-mediated inhibited state. Therefore, targeting the fusicoccin binding cavity of 14-3-3 by small-molecule compounds may offer an alternative strategy to suppress CaMKK2 activity by stabilizing its phosphorylation-mediated inhibited state.

• MeSH
• fosforylace účinky léků   MeSH
• glykosidy chemie   farmakologie   MeSH
• kinasa proteinkinasy závislé na vápníku a kalmodulinu chemie   metabolismus   MeSH
• krystalografie rentgenová MeSH
• lidé MeSH
• mapy interakcí proteinů účinky léků   MeSH
• proteiny 14-3-3 chemie   metabolismus   MeSH
• simulace molekulového dockingu MeSH
• vazba proteinů účinky léků   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Targeted regulation of protein levels is an important tool to investigate the role of proteins essential for cell function and development. In recent years, methods based on the Escherichia coli dihydrofolate reductase destabilization domain (ecDHFR DD) have been established and used in various cell types. ecDHFR DD destabilizes the fused protein of interest and causes its degradation by proteasomes, unless it is stabilized by a specific ligand, trimethoprim. In this work we developed an inducible protein stabilization system in Leishmania mexicana based on ecDHFR DD.

• MeSH
• aktivace transkripce * MeSH
• dihydrofolátreduktasa genetika   metabolismus   MeSH
• Escherichia coli enzymologie   genetika   MeSH
• Leishmania mexicana genetika   metabolismus   MeSH
• molekulární biologie metody   MeSH
• parazitologie metody   MeSH
• regulace genové exprese * MeSH
• rekombinantní proteiny genetika   metabolismus   MeSH
• trimethoprim metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH

Integral membrane proteins carry out essential functions in the cell, and their activities are often modulated by specific protein-lipid interactions in the membrane. Here, we elucidate the intricate role of cardiolipin (CDL), a regulatory lipid, as a stabilizer of membrane proteins and their complexes. Using the in silico-designed model protein TMHC4_R (ROCKET) as a scaffold, we employ a combination of molecular dynamics simulations and native mass spectrometry to explore the protein features that facilitate preferential lipid interactions and mediate stabilization. We find that the spatial arrangement of positively charged residues as well as local conformational flexibility are factors that distinguish stabilizing from non-stabilizing CDL interactions. However, we also find that even in this controlled, artificial system, a clear-cut distinction between binding and stabilization is difficult to attain, revealing that overlapping lipid contacts can partially compensate for the effects of binding site mutations. Extending our insights to naturally occurring proteins, we identify a stabilizing CDL site within the E. coli rhomboid intramembrane protease GlpG and uncover its regulatory influence on enzyme substrate preference. In this work, we establish a framework for engineering functional lipid interactions, paving the way for the design of proteins with membrane-specific properties or functions.

• MeSH
• DNA vazebné proteiny MeSH
• endopeptidasy metabolismus   chemie   genetika   MeSH
• Escherichia coli metabolismus   genetika   MeSH
• kardiolipiny * metabolismus   chemie   MeSH
• membránové proteiny * metabolismus   chemie   genetika   MeSH
• proteinové inženýrství * MeSH
• proteiny z Escherichia coli * metabolismus   chemie   genetika   MeSH
• simulace molekulární dynamiky MeSH
• vazba proteinů MeSH
• Publikační typ
• časopisecké články MeSH

Proline-tryptophan complexes derived from experimental structures are investigated by quantum chemical procedures known to properly describe the London dispersion energy. We study two geometrical arrangements: the "L-shaped", stabilized by an H-bond, and the "stacked-like", where the two residues are in parallel orientation without any H-bond. Interestingly, the interaction energies in both cases are comparable and very large ( approximately 7 kcal mol(-1)). The strength of stabilization in the stacked arrangement is rather surprising considering the fact that only one partner has an aromatic character. The interaction energy decomposition using the SAPT method further demonstrates the very important role of dispersion energy in such arrangement. To elucidate the structural features responsible for this unexpectedly large stabilization we examined the role of the nitrogen heteroatom and the importance of the cyclicity of the proline residue. We show that the electrostatic interaction due to the presence of the dipole, caused by the nitrogen heteroatom, contributes largely to the strength of the interaction. Nevertheless, the cyclic arrangement of proline, which allows for the largest amount of dispersive contact with the aromatic partner, also has a notable-effect. Geometry optimizations carried out for the "stacked-like" complexes show that the arrangements derived from protein structure are close to their gas phase optimum geometry, suggesting that the environment has only a minor effect on the geometry of the interaction. We conclude that the strength of proline non-covalent interactions, combined with this residue's rigidity, might be the explanation for its prominent role in protein stabilization and recognition processes.

• MeSH
• chemické modely MeSH
• financování organizované MeSH
• fyzikální chemie metody   MeSH
• konformace proteinů MeSH
• ligandy MeSH
• mapování interakce mezi proteiny MeSH
• molekulární konformace MeSH
• prolin chemie   MeSH
• proteiny chemie   MeSH
• statická elektřina MeSH
• terciární struktura proteinů MeSH
• tryptofan chemie   MeSH
• vazba proteinů MeSH
• vodíková vazba MeSH

p53 missense mutant proteins commonly show increased stability compared to wild-type p53, which is thought to depend largely on the inability of mutant p53 to induce the ubiquitin ligase MDM2. However, recent work using mouse models has shown that the accumulation of mutant p53 occurs only in tumour cells, indicating that stabilization requires additional factors. To clarify the stabilization of p53 mutants in tumours, we analysed factors that affect their folding and degradation. Although all missense mutants that we studied are more stable than wild-type p53, the levels correlate with individual structural characteristics, which may be reflected in different gain-of-function properties. In the absence of Hsp90 activity, the less stable unfolded p53 mutants preferentially associate in a complex with Hsp70 and CHIP (carboxy terminus of Hsp70-interacting protein), and we show that CHIP is responsible for ubiquitination and degradation of these mutants. The demonstration of a complex interplay between Hsp90, Hsp70 and CHIP that regulate the stability of different p53 mutant proteins improves our understanding of the pro-tumorigenic effects of increased Hsp90 activity during multi-stage carcinogenesis. Understanding the roles of Hsp90, Hsp70 and CHIP in cancers may also provide an important avenue through which to target p53 to enhance treatment of human cancers.

• MeSH
• benzochinony farmakologie   MeSH
• ELISA MeSH
• fibroblasty cytologie   metabolismus   MeSH
• financování organizované MeSH
• imunoblotting MeSH
• imunoprecipitace MeSH
• konformace proteinů MeSH
• kultivované buňky MeSH
• lidé MeSH
• makrocyklické laktamy farmakologie   MeSH
• mutace genetika   MeSH
• myši knockoutované MeSH
• myši MeSH
• nádorový supresorový protein p53 fyziologie   chemie   MeSH
• nádory metabolismus   patologie   MeSH
• proteiny tepelného šoku HSC70 genetika   metabolismus   MeSH
• proteiny tepelného šoku HSP90 antagonisté a inhibitory   genetika   metabolismus   MeSH
• protoonkogenní proteiny c-mdm2 fyziologie   MeSH
• ubikvitinace MeSH
• ubikvitinligasy genetika   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH

Direct interactions between proteins are essential for the regulation of their functions in biological pathways. Targeting the complex network of protein-protein interactions (PPIs) has now been widely recognized as an attractive means to therapeutically intervene in disease states. Even though this is a challenging endeavor and PPIs have long been regarded as "undruggable" targets, the last two decades have seen an increasing number of successful examples of PPI modulators, resulting in growing interest in this field. PPI modulation requires novel approaches and the integrated efforts of multiple disciplines to be a fruitful strategy. This perspective focuses on the hub-protein 14-3-3, which has several hundred identified protein interaction partners, and is therefore involved in a wide range of cellular processes and diseases. Here, we aim to provide an integrated overview of the approaches explored for the modulation of 14-3-3 PPIs and review the examples resulting from these efforts in both inhibiting and stabilizing specific 14-3-3 protein complexes by small molecules, peptide mimetics, and natural products.

• MeSH
• lidé MeSH
• objevování léků metody   MeSH
• proteiny 14-3-3 antagonisté a inhibitory   metabolismus   MeSH
• stabilita proteinů účinky léků   MeSH
• vazba proteinů MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH

Metody exprese a purifikace rekombinantních proteinů umožňují produkci a detailní charakterizaci proteinů v základním výzkumu během in vitro experimentů, ale také přípravu proteinů s terapeutickým využitím. Publikace shrnuje základní postupy od přípravy expresních vektorů až po techniku afinitní purifikace. Dále pojednává o vlastnostech různých prokaryotických a eukaryotických expresních systémů a možnostech jejich využití. Molekulární klonování, které slouží k přípravě expresních vektorů pro rekombinantní proteiny, umožňuje cíleně modifikovat vlastnosti těchto proteinů tak, aby byla usnadněna jejich purifikace a také pozměněna jejich stabilita, aktivita nebo funkce. V současné době je k dispozici široká škála metodických přístupů, jež umožňují rychlou a efektivní přípravu expresních vektorů. Zvolený produkční organizmus a způsob purifikace rekombinantního proteinu určují výběr expresního vektoru. První volbou často bývá expresní systém využívající bakterii Escherichia coli, jehož přednostmi jsou zejména technická, časová i finanční nenáročnost. Tento expresní systém není příliš vhodný pro produkci komplexních savčích proteinů, pro které jsou optimální expresní systémy založené na využití eukaryotických organizmů (kvasinky, hmyzí buňky nebo savčí buňky). Kultivace hmyzích a savčích buněk je však technicky i finančně náročná. Rekombinantní proteiny jsou purifikovány nejčastěji metodou afinitní chromatografie využívající specifickou interakci peptidu nebo proteinu s afinitní matricí. Tyto peptidy či proteiny jsou fúzovány s N‑ nebo C‑koncem purifikovaného proteinu. Purifikace probíhá ve třech krocích, kdy je rekombinantní protein prostřednictvím afinitních značek specificky zachycen na matrici chromatografické kolony, dále následuje promývací krok, po kterém je uvolněn z kolony čistý protein.

Production of recombinant proteins is essential for many applications in both basic research and also in medicine, where recombinant proteins are used as pharmaceuticals. This review sum­marizes procedures involved in recombinant protein expression and purification, including molecular cloning of target genes into expression vectors, selection of the appropriate expres­sion system, and protein purification techniques. Recombinant DNA technology allows protein engineering to modify protein stability, activity and function or to facilitate protein purification by affinity tag fusions. A wide range of cloning systems enabling fast and effective design of expression vectors is currently available. A first choice of protein expression system is usually the bacteria Escherichia coli. The main advantages of this prokaryotic expression system are low cost and simplicity; on the other hand this system is often unsuitable for production of complex mam­malian proteins. Protein expression mediated by eukaryotic cells (yeast, insect and mammalian cells) usually produces properly folded and posttranslationally modified proteins. How­ever, cultivation of insect and, especially, mammalian cells is time consuming and expensive. Affinity tagged recombinant proteins are purified efficiently using affinity chromatography. An affinity tag is a protein or peptide that mediates specific binding to a chromatography column, unbound proteins are removed during a washing step and pure protein is subsequently eluted. Key words: recombinant protein – molecular cloning – purification – expression system This work was supported by the European Regional Development Fund and the State Budget of the Czech Republic (RECAMO, CZ.1.05/2.1.00/03.0101) and by MH CZ – DRO (MMCI, 00209805). The authors declare they have no potential conflicts of interest concerning drugs, products, or services used in the study. The Editorial Board declares that the manuscript met the ICMJE “uniform requirements” for bio­medical papers. Submitted: 22. 1. 2014 Accepted: 20. 3. 2014

• Klíčová slova
• purifikace, expresní systém, expresní vektor,
• MeSH
• chromatografie afinitní MeSH
• Escherichia coli genetika   MeSH
• eukaryotické buňky MeSH
• exprese genu * MeSH
• genetická transkripce MeSH
• genetické vektory * MeSH
• klonování DNA * MeSH
• kultivační média MeSH
• kvasinky genetika   MeSH
• prokaryotické buňky MeSH
• proteinové inženýrství MeSH
• rekombinantní proteiny * genetika   chemická syntéza   MeSH
• virové proteiny genetika   MeSH
• Publikační typ
• práce podpořená grantem MeSH

• MeSH
• mícha chirurgie   MeSH
• nemoci míchy MeSH
• neurochirurgické výkony MeSH
• neurochirurgie MeSH
• poranění míchy MeSH

• Konspekt
• Patologie. Klinická medicína
• NLK Obory
• neurochirurgie