Cations in Human Rhinoviruses

Zhao, Rui; Hadfield, Andrea T.; Kremer, Marcia J.; Rossmann, Michael G.

doi:10.1006/viro.1996.8301

Cited by 28 publications

(26 citation statements)

References 18 publications

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“…The involvement of the DE loop of VP1 in the interaction with metal ions on the five-fold axis was found in the structures of all other rhinovirus analyzed. These cations were predicted to play a role in regulation of rhinovirus stability, although no conformational changes were observed in EGTA-treated virus structures [54]. In the 80S structure, the side chain of Asp1135 appears mostly disordered and no extra density is found to position any ion and/or solvent molecule in the region.…”

Section: Resultsmentioning

confidence: 98%

Insights into Minor Group Rhinovirus Uncoating: The X-ray Structure of the HRV2 Empty Capsid

et al. 2012

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Upon attachment to their respective receptor, human rhinoviruses (HRVs) are internalized into the host cell via different pathways but undergo similar structural changes. This ultimately results in the delivery of the viral RNA into the cytoplasm for replication. To improve our understanding of the conformational modifications associated with the release of the viral genome, we have determined the X-ray structure at 3.0 Å resolution of the end-stage of HRV2 uncoating, the empty capsid. The structure shows important conformational changes in the capsid protomer. In particular, a hinge movement around the hydrophobic pocket of VP1 allows a coordinated shift of VP2 and VP3. This overall displacement forces a reorganization of the inter-protomer interfaces, resulting in a particle expansion and in the opening of new channels in the capsid core. These new breaches in the capsid, opening one at the base of the canyon and the second at the particle two-fold axes, might act as gates for the externalization of the VP1 N-terminus and the extrusion of the viral RNA, respectively. The structural comparison between native and empty HRV2 particles unveils a number of pH-sensitive amino acid residues, conserved in rhinoviruses, which participate in the structural rearrangements involved in the uncoating process.

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Section: Resultsmentioning

confidence: 98%

Insights into Minor Group Rhinovirus Uncoating: The X-ray Structure of the HRV2 Empty Capsid

et al. 2012

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“…The pentagonal bipyramid conformation is common for Ca 2+ -binding proteins (Fig. S7), for example, the canonical EF-hand motif, the HRV (rhinovirus) protein (34,35), and the Ca 2+ ATPase (36). Ion selectivity is the result of highly specific ion binding to the permeation pathway (18), and we propose that the double carboxylate rings of MCU generate strong ion affinity through positive cooperativity.…”

Section: +mentioning

confidence: 91%

Ion and inhibitor binding of the double-ring ion selectivity filter of the mitochondrial calcium uniporter

Cao

Wang

Cui

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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The calcium (Ca 2+ ) uniporter of mitochondria is a holocomplex consisting of the Ca 2+ -conducting channel, known as mitochondrial calcium uniporter (MCU), and several accessory and regulatory components. A previous electrophysiology study found that the uniporter has high Ca 2+ selectivity and conductance and this depends critically on the conserved amino acid sequence motif, DXXE (Asp-X-X-Glu) of MCU. A recent NMR structure of the MCU channel from Caenorhabditis elegans revealed that the DXXE forms two parallel carboxylate rings at the channel entrance that seem to serve as the ion selectivity filter, although direct ion interaction of this structural motif has not been addressed. Here, we use a paramagnetic probe, manganese (Mn 2+ ), to investigate ion and inhibitor binding of this putative selectivity filter. Our paramagnetic NMR data show that mutants with a single carboxylate ring, NXXE (Asn-X-X-Glu) and DXXQ (Asp-X-X-Gln), each can bind Mn 2+ specifically, whereas in the WT the two rings bind Mn 2+ cooperatively, resulting in ∼1,000-fold higher apparent affinity. Ca 2+ can specifically displace the bound Mn 2+ at the DXXE site in the channel. Furthermore, titrating the sample with the known channel inhibitor ruthenium 360 (Ru360) can displace Mn 2+ binding from the solventaccessible Asp site but not the inner Glu site. The NMR titration data, together with structural analysis of the DXXE motif and molecular dynamics simulation, indicate that the double carboxylate rings at the apex of the MCU pore constitute the ion selectivity filter and that Ru360 directly blocks ion entry into the filter by binding to the outer carboxylate ring.) uptake by mitochondria is a long-known physiological phenomenon that is important for regulating various cellular activities such as aerobic metabolism and cell death (1-3). This uptake of Ca 2+ is achieved by a Ca 2+ uniporter whose activity can be blocked by ruthenium red (RuR) or ruthenium 360 (Ru360) (4). It was later shown by patch-clamping the inner mitochondrial membrane that this uniporter achieves remarkably high Ca 2+ conductance and selectivity (5). Only about 5 y ago was the molecular identity of the channel component of the uniporter identified using integrative genomics approaches (6, 7). This channel is commonly referred to as the mitochondrial calcium uniporter (MCU). In metazoans, however, the uniporter is much more complex than just the pore-forming subunit; it is a holocomplex (also called a uniplex) containing other regulatory components. Among them, the single-pass transmembrane (TM) protein EMRE (Essential MCU REgulator) is absolutely required for the MCU to conduct ions (8). Two soluble components in the intermembrane space, MICU1 and MICU2, are Ca 2+ -sensing proteins that gate the activity of MCU based on outside Ca 2+ concentrations through EMRE (9-12). The current consensus is that the minimum requirements for uniporter-mediated Ca 2+ flux in metazoans are MCU and EMRE, whereas in lower organisms such as Dictyostelium that lack EMRE, MCU i...

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“…Several reports have demonstrated that disulfide linkage and calcium ion-mediated interactions between the capsid protein subunits are important for virion assembly [7–11]. In Simian virus 40 (SV40), the capsids can dissociate into VP1 pentamers in vitro in the presence of dithiothreitol (DTT) and ethylene glycol tetraacetic acid (EGTA) [8, 12–15].…”

Section: Introductionmentioning

confidence: 99%

Roles of cysteines Cys115 and Cys201 in the assembly and thermostability of grouper betanodavirus particles

Wang

Hsu

et al. 2010

Virus Genes

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The virus-like particle (VLP) assembled from capsid subunits of the dragon grouper nervous necrosis virus (DGNNV) is very similar to its native T = 3 virion. In order to investigate the effects of four cysteine residues in the capsid polypeptide on the assembly/dissociation pathways of DGNNV virions, we recombinantly cloned mutant VLPs by mutating each cysteine to destroy the specific disulfide linkage as compared with thiol reduction to destroy all S–S bonds. The mutant VLPs of C187A and C331A mutations were similar to wild-type VLPs (WT-VLPs); hence, the effects of Cys187 and Cys331 on the particle formation and thermostability were presumably negligible. Electron microscopy showed that either C115A or C201A mutation disrupted de novo VLP formation significantly. As shown in micrographs and thermal decay curves, β-mercaptoethanol-treated WT-VLPs remained intact, merely resulting in lower tolerance to thermal disruption than native WT-VLPs. This thiol reduction broke disulfide linkages inside the pre-fabricated VLPs, but it did not disrupt the appearance of icosahedrons. Small dissociated capsomers from EGTA-treated VLPs were able to reassemble back to icosahedrons in the presence of calcium ions, but additional treatment with β-mercaptoethanol during EGTA dissociation resulted in inability of the capsomers to reassemble into the icosahedral form. These results indicated that Cys115 and Cys201 were essential for capsid formation of DGNNV icosahedron structure in de novo assembly and reassembly pathways, as well as for the thermal stability of pre-fabricated particles.

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Cations in Human Rhinoviruses

Cited by 28 publications

References 18 publications

Insights into Minor Group Rhinovirus Uncoating: The X-ray Structure of the HRV2 Empty Capsid

Insights into Minor Group Rhinovirus Uncoating: The X-ray Structure of the HRV2 Empty Capsid

Ion and inhibitor binding of the double-ring ion selectivity filter of the mitochondrial calcium uniporter

Roles of cysteines Cys115 and Cys201 in the assembly and thermostability of grouper betanodavirus particles

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