| 1. |
- Di Trani, Justin M., et al.
(författare)
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Rieske head domain dynamics and indazole-derivative inhibition of Candida albicans complex III
- 2022
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Ingår i: Structure. - : Elsevier BV. - 0969-2126 .- 1878-4186. ; 30:1, s. 129-138
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Tidskriftsartikel (refereegranskat)abstract
- Electron transfer between respiratory complexes drives transmembrane proton translocation, which powers ATP synthesis and membrane transport. The homodimeric respiratory complex III (CIII2) oxidizes ubiquinol to ubiquinone, transferring electrons to cytochrome c and translocating protons through a mechanism known as the Q cycle. The Q cycle involves ubiquinol oxidation and ubiquinone reduction at two different sites within each CIII monomer, as well as movement of the head domain of the Rieske subunit. We determined structures of Candida albicans CIII2 by cryoelectron microscopy (cryo-EM), revealing endogenous ubiquinone and visualizing the continuum of Rieske head domain conformations. Analysis of these conformations does not indicate cooperativity in the Rieske head domain position or ligand binding in the two CIIIs of the CIII2 dimer. Cryo-EM with the indazole derivative Inz-5, which inhibits fungal CIII2 and is fungicidal when administered with fungistatic azole drugs, showed that Inz-5 inhibition alters the equilibrium of Rieske head domain positions.
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| 2. |
- Doran, Matthew H., et al.
(författare)
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Three structural solutions for bacterial adhesion pilus stability and superelasticity
- 2023
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Ingår i: Structure. - : Elsevier. - 0969-2126 .- 1878-4186.
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Tidskriftsartikel (refereegranskat)abstract
- Bacterial adhesion pili are key virulence factors that mediate host-pathogen interactions in diverse epithelial environments. Deploying a multimodal approach, we probed the structural basis underpinning the biophysical properties of pili originating from enterotoxigenic (ETEC) and uropathogenic bacteria. Using cryo-electron microscopy we solved the structures of three vaccine target pili from ETEC bacteria, CFA/I, CS17, and CS20. Pairing these and previous pilus structures with force spectroscopy and steered molecular dynamics simulations, we find a strong correlation between subunit-subunit interaction energies and the force required for pilus unwinding, irrespective of genetic similarity. Pili integrate three structural solutions for stabilizing their assemblies: layer-to-layer interactions, N-terminal interactions to distant subunits, and extended loop interactions from adjacent subunits. Tuning of these structural solutions alters the biophysical properties of pili and promotes the superelastic behavior that is essential for sustained bacterial attachment.
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| 3. |
- Hellmich, Ute A., et al.
(författare)
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TRP channels : branching out into the fungal kingdom
- 2022
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Ingår i: Structure. - : Elsevier BV. - 0969-2126 .- 1878-4186. ; 30:1, s. 2-4
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- TRP channels have been heavily pursued as cryo-electron microscopy targets since they rang in the "resolution revolution."Although widespread in eukaryotes, a fungal TRP channel structure was missing. In this issue of Structure, Ahmed et al. (2022) present structural insights into the regulation of yeast TRPY1 by Ca2+ and lipids.
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| 4. |
- Isaksson, Linnéa, et al.
(författare)
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Signaling Mechanism of Phytochromes in Solution.
- 2021
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Ingår i: Structure. - : Elsevier BV. - 1878-4186 .- 0969-2126. ; 29:2, s. 151-160
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Tidskriftsartikel (refereegranskat)abstract
- Phytochrome proteins guide the red/far-red photoresponse of plants, fungi, and bacteria. Crystal structures suggest that the mechanism of signal transduction from the chromophore to the output domains involves refolding of the so-called PHY tongue. It is currently not clear how the two other notable structural features of the phytochrome superfamily, the so-called helical spine and a knot in the peptide chain, are involved in photoconversion. Here, we present solution NMR data of the complete photosensory core module from Deinococcus radiodurans. Photoswitching between the resting and the active states induces changes in amide chemical shifts, residual dipolar couplings, and relaxation dynamics. All observables indicate a photoinduced structural change in the knot region and lower part of the helical spine. This implies that a conformational signal is transduced from the chromophore to the helical spine through the PAS and GAF domains. The discovered pathway underpins functional studies of plant phytochromes and may explain photosensing by phytochromes under biological conditions.
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| 5. |
- Jung, Taeyang, et al.
(författare)
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The Polyglutamine Expansion at the N-Terminal of Huntingtin Protein Modulates the Dynamic Configuration and Phosphorylation of the C-Terminal HEAT Domain
- 2020
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Ingår i: Structure. - : Cell Press. - 0969-2126 .- 1878-4186. ; 28:9, s. 1035-1050.e8
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Tidskriftsartikel (refereegranskat)abstract
- The polyQ expansion in huntingtin protein (HTT) is the prime cause of Huntington's disease (HD). The recent cryoelectron microscopy (cryo-EM) structure of HTT-HAP40 complex provided the structural information on its HEAT-repeat domains. Here, we present analyses of the impact of polyQ length on the structure and function of HTT via an integrative structural and biochemical approach. The cryo-EM analysis of normal (Q23) and disease (Q78) type HTTs shows that the structures of apo HTTs significantly differ from the structure of HTT in a HAP40 complex and that the polyQ expansion induces global structural changes in the relative movements among the HTT domains. In addition, we show that the polyQ expansion alters the phosphorylation pattern across HTT and that Ser2116 phosphorylation in turn affects the global structure and function of HTT These results provide a molecular basis for the effect of the polyQ segment on HTT structure and activity, which may be important for HTT pathology.
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| 6. |
- Jäger, Franziska, et al.
(författare)
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Structure of the enterococcal T4SS protein PrgL reveals unique dimerization interface in the VirB8 protein family
- 2022
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Ingår i: Structure. - : Elsevier BV. - 0969-2126 .- 1878-4186. ; 30:6, s. 876-885.e5
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Tidskriftsartikel (refereegranskat)abstract
- Multidrug-resistant bacteria pose serious problems in hospital-acquired infections (HAIs). Most antibiotic resistance genes are acquired via conjugative gene transfer, mediated by type 4 secretion systems (T4SS). Although most multidrug-resistant bacteria responsible for HAIs are of Gram-positive origin, with enterococci being major contributors, mostly Gram-negative T4SSs have been characterized. Here, we describe the structure and organization of PrgL, a core protein of the T4SS channel, encoded by the pCF10 plasmid from Enterococcus faecalis. The structure of PrgL displays similarity to VirB8 proteins of Gram-negative T4SSs. In vitro experiments show that the soluble domain alone is enough to drive both dimerization and dodecamerization, with a dimerization interface that differs from all other known VirB8-like proteins. In vivo experiments verify the importance of PrgL dimerization. Our findings provide insight into the molecular building blocks of Gram-positive T4SS, highlighting similarities but also unique features in PrgL compared to other VirB8-like proteins.
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| 7. |
- Kaldmäe, Margit, et al.
(författare)
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A “spindle and thread” mechanism unblocks p53 translation by modulating N-terminal disorder
- 2022
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Ingår i: Structure. - : Elsevier BV. - 0969-2126 .- 1878-4186. ; 30:5, s. 733-742, e1-e7
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Tidskriftsartikel (refereegranskat)abstract
- Disordered proteins pose a major challenge to structural biology. A prominent example is the tumor suppressor p53, whose low expression levels and poor conformational stability hamper the development of cancer therapeutics. All these characteristics make it a prime example of “life on the edge of solubility.” Here, we investigate whether these features can be modulated by fusing the protein to a highly soluble spider silk domain (NT∗). The chimeric protein displays highly efficient translation and is fully active in human cancer cells. Biophysical characterization reveals a compact conformation, with the disordered transactivation domain of p53 wrapped around the NT∗ domain. We conclude that interactions with NT∗ help to unblock translation of the proline-rich disordered region of p53. Expression of partially disordered cancer targets is similarly enhanced by NT∗. In summary, we demonstrate that inducing co-translational folding via a molecular “spindle and thread” mechanism unblocks protein translation in vitro.
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| 8. |
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| 9. |
- Moe, Agnes, et al.
(författare)
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The respiratory supercomplex from C. glutamicum
- 2022
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Ingår i: Structure. - : Elsevier BV. - 0969-2126 .- 1878-4186. ; 30:3, s. 338-349
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Tidskriftsartikel (refereegranskat)abstract
- Corynebacterium glutamicum is a preferentially aerobic gram-positive bacterium belonging to the phylum Actinobacteria, which also includes the pathogen Mycobacterium tuberculosis. In these bacteria, respiratory complexes III and IV form a CIII2CIV2 supercomplex that catalyzes oxidation of menaquinol and reduction of dioxygen to water. We isolated the C. glutamicum supercomplex and used cryo-EM to determine its structure at 2.9 Å resolution. The structure shows a central CIII2 dimer flanked by a CIV on two sides. A menaquinone is bound in each of the QN and QP sites in each CIII and an additional menaquinone is positioned ∼14 Å from heme bL. A di-heme cyt. cc subunit electronically connects each CIII with an adjacent CIV, with the Rieske iron-sulfur protein positioned with the iron near heme bL. Multiple subunits interact to form a convoluted sub-structure at the cytoplasmic side of the supercomplex, which defines a path for proton transfer into CIV.
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| 10. |
- Okamoto, Kenta, et al.
(författare)
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Acquired Functional Capsid Structures in Metazoan Totivirus-like dsRNA Virus
- 2020
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Ingår i: Structure. - : Elsevier BV. - 0969-2126 .- 1878-4186. ; 28:8, s. 888-
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Tidskriftsartikel (refereegranskat)abstract
- Non-enveloped icosahedral double-stranded RNA (dsRNA) viruses possess multifunctional capsids required for their proliferation. Whereas protozoan/fungal dsRNA viruses have a relatively simple capsid structure, which suffices for the intracellular phase in their life cycle, metazoan dsRNA viruses have acquired additional structural features as an adaptation for extracellular cell-to-cell transmission in multicellular hosts. Here, we present the first atomic model of a metazoan dsRNA totivirus-like virus and the structure reveals three unique structural traits: a C-terminal interlocking arm, surface projecting loops, and an obstruction at the pore on the 5-fold symmetry axis. These traits are keys to understanding the capsid functions of metazoan dsRNA viruses, such as particle stability and formation, cell entry, and endogenous intraparticle transcription of mRNA. On the basis of molecular dynamics simulations of the obstructed pore, we propose a possible mechanism of intraparticle transcription in totivirus-like viruses, which dynamically switches between open and closed states of the pore(s).
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