Talk of Dr. Alcicek on Zero- and Ultralow-field NMR
We are pleased to announce that the third Kiel Imaging Seminar (KIS) will take place next Monday, Jan. 16th.
A gateway to realm of structural data for biochemists, biophysicists, molecular biologist, and all scientists whose research benefits from accurate structure determination of biological macromolecules, assemblies, and complex molecular machineries at atomic resolution.
Open access to 10 high-end core facilities and assisted expertise in NMR, X-ray crystallography and crystallization, cryo-electron microscopy and tomography, biophysical characterization of biomolecular interaction, nanobiotechnology, proteomics and structural mass spectrometry.
A distributed infrastructure constituted by Core Facilities of CEITEC (Central European Institute of Technology), located in Brno, and BIOCEV (Biotechnology and Biomedicine Centre), located in Vestec near Prague, Central Bohemia.
We are pleased to announce that the third Kiel Imaging Seminar (KIS) will take place next Monday, Jan. 16th.
Instruct allocates funds to support small pilot research and development projects in any area of structural biology up to a maximum of €15,000 per project.
The EMBO workshop "Visualising the complex dynamics of biological membranes” is on March 13-16, at the Tel Aviv University.
Early career researchers, please submit abstracts for short talks. The program features a 'Dinner with speakers' event, with a chance for students and postdocs looking for a next career step, as well as PIs interested in new team members to discuss more informally. There will also be a tour to Jerusalem or hiking around the Dead Sea on the 15th for a full day.
The meeting will highlight the latest discoveries in structural and membrane biology along with a view to the future of how to tackle questions of higher complexity. The program will combine recent progress in single particle analysis, tomography, advances in molecular simulations, and high-speed atomic force microscopy.
A. Schenkmayerova, et al.: Catalytic mechanism for Renilla-type luciferases, Nat. Catal. (2023). https://doi.org/10.1038/s41929-022-00895-z
M. Stiborek, et al.: Infrared Laser Desorption of Intact Nanoparticles for Digital Tissue Imaging Anal. Chem. (2022) 94, 51, 18114 – 18121, https://doi.org/10.1021/acs.analchem.2c05216
P.M. Szczepanik, et al.: Convergent Assembly of the Tricyclic Labdane Core Enables Synthesis of Diverse Forskolin-like Molecules, Angew. Chem. Int. Ed. (2022), https://doi.org/10.1002/anie.202213183
V. Siahaan, et al.: Microtubule lattice spacing governs cohesive envelope formation of tau family proteins, Nat. Chem. Biol., 18 (2022) 1224-+, 10.1038/s41589-022-01096-2
O. Gahura, et al.: An ancestral interaction module promotes oligomerization in divergent mitochondrial ATP synthases, Nature Communications, 13 (2022) 13, 10.1038/s41467-022-33588-z
The national conference with focus on structural biology in Nové Hrady, South Bohemia.
NMR in Valtice is the annual meeting of the nuclear magnetic resonance community and serves as the principal international forum for reporting outstanding research and development on new NMR methods, techniques and tools for research and application in science and technology.
the best of science obtained using CIISB Core Facilities
The mechanism of Renilla-type luciferase reaction and its inhibition.
The widely used coelenterazine-powered Renilla luciferase was discovered over 40 years ago, but the oxidative mechanism by which it generates blue photons remains unclear. Here we decipher Renilla-type catalysis through crystallographic, spectroscopic and computational experiments. Structures of ancestral and extant luciferases complexed with the substrate-like analogue azacoelenterazine or a reaction product were obtained, providing molecular snapshots of coelenterazine-to-coelenteramide oxidation. Bound coelenterazine adopts a Y-shaped conformation, enabling the deprotonated imidazopyrazinone component to attack O2 via a radical charge-transfer mechanism. A high emission intensity is secured by an aspartate from a conserved proton-relay system, which protonates the excited coelenteramide product. Another aspartate on the rim of the catalytic pocket fine-tunes the electronic state of coelenteramide and promotes the formation of the blue light-emitting phenolate anion. The results obtained also reveal structural features distinguishing flash-type from glow-type bioluminescence, providing insights that will guide the engineering of next-generation luciferase‒luciferin pairs for ultrasensitive optical bioassays.
Schenkmayerova, A., Toul, M., Pluskal, D., Baatallah, R., Gagnot, G., Pinto, G.P., Santana, V.T., Stuchla, M., Neugebauer, P., Chaiyen, P., Damborsky, J., Bednar, D., Janin, Y.L., Prokop, Z. & Marek, M.: Catalytic mechanism for Renilla-type luciferases, Nat. Catal. (2023). https://doi.org/10.1038/s41929-022-00895-z
A new technique for the digital mapping of biomarkers in tissues based on desorption and counting intact gold nanoparticle (Au NP) tags using infrared laser ablation single - particle inductively coupled plasma mass spectrometry (IR LA SP ICP MS).
In contrast to conventional UV laser ablation, Au NPs are not disintegrated during the desorption process due to their low absorption at 2940 nm. A mass spectrometer detects up to 83% of Au NPs. The technique is demonstrated on mapping a proliferation marker, nuclear protein Ki-67, in three-dimensional (3D) aggregates of colorectal carcinoma cells, and the results are compared with confocal fluorescence microscopy and UV LA ICP MS. Precise counting of 20 nm Au NPs with a single-particle detection limit in each pixel by the new approach generates sharp distribution maps of a specific biomarker in the tissue. Advantageously, the desorption of Au NPs from regions outside the tissue is strongly suppressed. The developed methodology promises multiplex mapping of low-abundant biomarkers in numerous biological and medical applications using multielemental mass spectrometers.
Stiborek, M., Jindřichová, L., Meliorisová, S., Bednařík, A., Prysiazhnyi, V., Kroupa, J., Houška, P., Adamová, B., Navrátilová, J., Kanický, V., and Preisler, J.:
Infrared Laser Desorption of Intact Nanoparticles for Digital Tissue Imaging
Anal. Chem. 2022 94, 51, 18114 – 18121, https://doi.org/10.1021/acs.analchem.2c05216
Labdane-type terpenes are a large family of bioactive natural products. Their often-complex structures present challenges to semisynthesis and de novo chemical synthesis in search of analogs with improved properties. To enable new modifications of the well-known tricyclic terpene forskolin, we have developed a distinct and potentially general synthetic scheme for the preparation of analogs of complex labdanes.
We report a new synthetic strategy for the flexible preparation of forskolin-like molecules. The approach is different from the previously published works and employs a convergent assembly of the tricyclic labdane-type core from pre-functionalized cyclic building blocks. Stereoselective Michael addition enabled the fragment coupling with excellent control over three newly created contiguous stereocenters, all-carbon quaternary centers included. Silyl enol ether-promoted ring-opening metathesis paired with ring closure were the other key steps enabling concise assembly of the tricyclic core. Late-stage functionalization sequences transformed the tricyclic intermediates into a set of different forskolin-like molecules. The modular nature of the synthetic scheme described herein has the potential to become a general platform for the preparation of analogs of forskolin and other complex tricyclic labdanes.
Szczepanik, P. M., Mikhaylov, A. A., Hylse, O., Kučera, R., Daďová, P., Nečas, M., Kubala, L., Paruch, K., and Švenda, J.:
Convergent Assembly of the Tricyclic Labdane Core Enables Synthesis of Diverse Forskolin-like Molecules, Angew. Chem. Int. Ed. 2022, on-line version e202213183, https://doi.org/10.1002/anie.202213183
literature to read, science to follow
In this section, a distinct selection of six highly stimulating research publications and reviews published during past 6 months is presented. It is our hope that links to exciting science, which deserves attention of the structural biology community, will help you to locate gems in the steadily expanding jungle of scientific literature. You are welcome to point out to any paper you found interesting by sending a link or citation to email@example.com. The section is being updated regularly.
The flagella of mammalian sperm display non-planar, asymmetric beating, in contrast to the planar, symmetric beating of flagella from sea urchin sperm and unicellular organisms. The molecular basis of this difference is unclear. Here, we perform in situ cryo-electron tomography of mouse and human sperm, providing the highest-resolution structural information to date. Our subtomogram averages reveal mammalian sperm-specific protein complexes within the microtubules, the radial spokes and nexin–dynein regulatory complexes. The locations and structures of these complexes suggest potential roles in enhancing the mechanical strength of mammalian sperm axonemes and regulating dynein-based axonemal bending. Intriguingly, we find that each of the nine outer microtubule doublets is decorated with a distinct combination of sperm-specific complexes. We propose that this asymmetric distribution of proteins differentially regulates the sliding of each microtubule doublet and may underlie the asymmetric beating of mammalian sperm.
The ATP-dependent ring-shaped chaperonin TRiC/CCT is essential for cellular proteostasis. To uncover why some eukaryotic proteins can only fold with TRiC assistance, we reconstituted the folding of β-tubulin using human prefoldin and TRiC. We find unstructured β-tubulin is delivered by prefoldin to the open TRiC chamber followed by ATP-dependent chamber closure. Cryo-EM resolves four near-atomic-resolution structures containing progressively folded β-tubulin intermediates within the closed TRiC chamber, culminating in native tubulin. This substrate folding pathway appears closely guided by site-specific interactions with conserved regions in the TRiC chamber. Initial electrostatic interactions between the TRiC interior wall and both the folded tubulin N domain and its C-terminal E-hook tail establish the native substrate topology, thus enabling C-domain folding. Intrinsically disordered CCT C termini within the chamber promote subsequent folding of tubulin’s core and middle domains and GTP-binding. Thus, TRiC’s chamber provides chemical and topological directives that shape the folding landscape of its obligate substrates.
RNA modifications are widespread in biology and abundant in ribosomal RNA. However, the importance of these modifications is not well understood. We show that methylation of a single nucleotide, in the catalytic center of the large subunit, gates ribosome assembly. Massively parallel mutational scanning of the essential nuclear GTPase Nog2 identified important interactions with rRNA, particularly with the 2′-O-methylated A-site base Gm2922. We found that methylation of G2922 is needed for assembly and efficient nuclear export of the large subunit. Critically, we identified single amino acid changes in Nog2 that completely bypass dependence on G2922 methylation and used cryoelectron microscopy to directly visualize how methylation flips Gm2922 into the active site channel of Nog2. This work demonstrates that a single RNA modification is a critical checkpoint in ribosome biogenesis, suggesting that such modifications can play an important role in regulation and assembly of macromolecular machines.
Camelid single-domain antibodies, also known as nanobodies, can be readily isolated from naïve libraries for specific targets but often bind too weakly to their targets to be immediately useful. Laboratory-based genetic engineering methods to enhance their affinity, termed maturation, can deliver useful reagents for different areas of biology and potentially medicine. Using the receptor binding domain (RBD) of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein and a naïve library, we generated closely related nanobodies with micromolar to nanomolar binding affinities. By analyzing the structure–activity relationship using X-ray crystallography, cryoelectron microscopy, and biophysical methods, we observed that higher conformational entropy losses in the formation of the spike protein–nanobody complex are associated with tighter binding.To investigate this, we generated structural ensembles of the different complexes from electron microscopy maps and correlated the conformational fluctuations with binding affinity. This insight guided the engineering of a nanobody with improved affinity for the spike protein.
Leucine-rich repeat kinase 2 (LRRK2) is one of the most commonly mutated genes in familial Parkinson’s disease (PD). Under some circumstances, LRRK2 co-localizes with microtubules in cells, an association enhanced by PD mutations. We report a cryo-EM structure of the catalytic half of LRRK2, containing its kinase, in a closed conformation, and GTPase domains, bound to microtubules. We also report a structure of the catalytic half of LRRK1, which is closely related to LRRK2 but is not linked to PD. Although LRRK1’s structure is similar to that of LRRK2, we find that LRRK1 does not interact with microtubules. Guided by these structures, we identify amino acids in LRRK2’s GTPase that mediate microtubule binding; mutating them disrupts microtubule binding in vitro and in cells, without affecting LRRK2’s kinase activity. Our results have implications for the design of therapeutic LRRK2 kinase inhibitors.
Drug-drug interaction of the antiviral sofosbuvir and the antiarrhythmics amiodarone has been reported to cause fatal heartbeat slowing. Sofosbuvir and its analog, MNI-1, were reported to potentiate the inhibition of cardiomyocyte calcium handling by amiodarone, which functions as a multi-channel antagonist, and implicate its inhibitory effect on L-type Cav channels, but the molecular mechanism has remained unclear. Here we present systematic cryo-EM structural analysis of Cav1.1 and Cav1.3 treated with amiodarone or sofosbuvir alone, or sofosbuvir/MNI-1 combined with amiodarone. Whereas amiodarone alone occupies the dihydropyridine binding site, sofosbuvir is not found in the channel when applied on its own. In the presence of amiodarone, sofosbuvir/MNI-1 is anchored in the central cavity of the pore domain through specific interaction with amiodarone and directly obstructs the ion permeation path. Our study reveals the molecular basis for the physical, pharmacodynamic interaction of two drugs on the scaffold of Cavchannels.
“Science is a wonderful thing if one does not have to earn one's living at it.”Albert Einstein