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Open Access
Abstract: Synaptic vesicle (SV) fusion with the plasma membrane (PM) proceeds through intermediate steps that remain poorly resolved. The effect of persistent high or low exocytosis activity on intermediate steps remains unknown. Using spray-mixing plunge-freezing cryo-electron tomography we observe events following synaptic stimulation at nanometer resolution in near-native samples. Our data suggest that during the stage that immediately follows stimulation, termed early fusion, PM and SV membrane curvature changes to establish a point contact. The next stage—late fusion—shows fusion pore opening and SV collapse. During early fusion, proximal tethered SVs form additional tethers with the PM and increase the inter-SV connector number. In the late-fusion stage, PM-proximal SVs lose their interconnections, allowing them to move toward the PM. Two SNAP-25 mutations, one arresting and one disinhibiting spontaneous release, cause connector loss. The disinhibiting mutation causes loss of membrane-proximal multiple-tethered SVs. Overall, tether formation and connector dissolution are triggered by stimulation and respond to spontaneous fusion rate manipulation. These morphological observations likely correspond to SV transition from one functional pool to another.
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Mar 2023
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Krios I-Titan Krios I at Diamond
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Open Access
Abstract: Cryo-electron tomography (cryo-ET) has been gaining momentum in recent years, especially since the introduction of direct electron detectors, improved automated acquisition strategies, preparative techniques that expand the possibilities of what the electron microscope can image at high-resolution using cryo-ET and new subtomogram averaging software. Additionally, data acquisition has become increasingly streamlined, making it more accessible to many users. The SARS-CoV-2 pandemic has further accelerated remote cryo-electron microscopy (cryo-EM) data collection, especially for single-particle cryo-EM, in many facilities globally, providing uninterrupted user access to state-of-the-art instruments during the pandemic. With the recent advances in Tomo5 (software for 3D electron tomography), remote cryo-ET data collection has become robust and easy to handle from anywhere in the world. This article aims to provide a detailed walk-through, starting from the data collection setup in the tomography software for the process of a (remote) cryo-ET data collection session with detailed troubleshooting. The (remote) data collection protocol is further complemented with the workflow for structure determination at near-atomic resolution by subtomogram averaging with emClarity, using apoferritin as an example.
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Jul 2022
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B24-Cryo Soft X-ray Tomography
Krios II-Titan Krios II at Diamond
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Luiza
Mendonca
,
Andrew
Howe
,
James B.
Gilchrist
,
Yuewen
Sheng
,
Dapeng
Sun
,
Michael L.
Knight
,
Laura C.
Zanetti-Domingues
,
Benji
Bateman
,
Anna-Sophia
Krebs
,
Long
Chen
,
Julika
Radecke
,
Vivian D.
Li
,
Tao
Ni
,
Ilias
Kounatidis
,
Mohamed A.
Koronfel
,
Marta
Szynkiewicz
,
Maria
Harkiolaki
,
Marisa
Martin-Fernandez
,
William
James
,
Peijun
Zhang
Diamond Proposal Number(s):
[21004, 26987]
Open Access
Abstract: Since the outbreak of the SARS-CoV-2 pandemic, there have been intense structural studies on purified viral components and inactivated viruses. However, structural and ultrastructural evidence on how the SARS-CoV-2 infection progresses in the native cellular context is scarce, and there is a lack of comprehensive knowledge on the SARS-CoV-2 replicative cycle. To correlate cytopathic events induced by SARS-CoV-2 with virus replication processes in frozen-hydrated cells, we established a unique multi-modal, multi-scale cryo-correlative platform to image SARS-CoV-2 infection in Vero cells. This platform combines serial cryoFIB/SEM volume imaging and soft X-ray cryo-tomography with cell lamellae-based cryo-electron tomography (cryoET) and subtomogram averaging. Here we report critical SARS-CoV-2 structural events – e.g. viral RNA transport portals, virus assembly intermediates, virus egress pathway, and native virus spike structures, in the context of whole-cell volumes revealing drastic cytppathic changes. This integrated approach allows a holistic view of SARS-CoV-2 infection, from the whole cell to individual molecules.
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Jul 2021
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I03-Macromolecular Crystallography
Krios I-Titan Krios I at Diamond
|
Wanwisa
Dejnirattisai
,
Daming
Zhou
,
Helen M.
Ginn
,
Helen M. E.
Duyvesteyn
,
Piyada
Supasa
,
James Brett
Case
,
Yuguang
Zhao
,
Thomas
Walter
,
Alexander J.
Mentzer
,
Chang
Liu
,
Beibei
Wang
,
Guido C.
Paesen
,
Jose
Slon-Campos
,
César
López-Camacho
,
Natasha M.
Kafai
,
Adam L.
Bailey
,
Rita E.
Chen
,
Baoling
Ying
,
Craig
Thompson
,
Jai
Bolton
,
Alex
Fyfe
,
Sunetra
Gupta
,
Tiong Kit
Tan
,
Javier
Gilbert-Jaramillo
,
William
James
,
Michael
Knight
,
Miles W.
Carroll
,
Donal
Skelly
,
Christina
Dold
,
Yanchun
Peng
,
Robert
Levin
,
Tao
Dong
,
Andrew J.
Pollard
,
Julian C.
Knight
,
Paul
Klenerman
,
Nigel
Temperton
,
David R.
Hall
,
Mark A.
Williams
,
Neil G.
Paterson
,
Felicity
Bertram
,
C. Alistair
Siebert
,
Daniel K.
Clare
,
Andrew
Howe
,
Julika
Radecke
,
Yun
Song
,
Alain R.
Townsend
,
Kuan-Ying A.
Huang
,
Elizabeth E.
Fry
,
Juthathip
Mongkolsapaya
,
Michael S.
Diamond
,
Jingshan
Ren
,
David I.
Stuart
,
Gavin R.
Screaton
Diamond Proposal Number(s):
[27009, 26983]
Open Access
Abstract: Antibodies are crucial to immune protection against SARS-CoV-2, with some in emergency use as therapeutics. Here we identify 377 human monoclonal antibodies (mAbs) recognizing the virus spike, and focus mainly on 80 that bind the receptor binding domain (RBD). We devise a competition data driven method to map RBD binding sites. We find that although antibody binding sites are widely dispersed, neutralizing antibody binding is focused, with nearly all highly inhibitory mAbs (IC50<0.1μg/ml) blocking receptor interaction, except for one that binds a unique epitope in the N-terminal domain. Many of these neutralizing mAbs use public V-genes and are close to germline. We dissect the structural basis of recognition for this large panel of antibodies through X-ray crystallography and cryo-electron microscopy of 19 Fab-antigen structures. We find novel binding modes for some potently inhibitory antibodies and demonstrate that strongly neutralizing mAbs protect, prophylactically or therapeutically, in animal models.
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Feb 2021
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I03-Macromolecular Crystallography
Krios I-Titan Krios I at Diamond
|
Daming
Zhou
,
Helen M. E.
Duyvesteyn
,
Cheng-Pin
Chen
,
Chung-Guei
Huang
,
Ting-Hua
Chen
,
Shin-Ru
Shih
,
Yi-Chun
Lin
,
Chien-Yu
Cheng
,
Shu-Hsing
Cheng
,
Yhu-Chering
Huang
,
Tzou-Yien
Lin
,
Che
Ma
,
Jiandong
Huo
,
Loic
Carrique
,
Tomas
Malinauskas
,
Reinis R.
Ruza
,
Pranav
Shah
,
Tiong Kit
Tan
,
Pramila
Rijal
,
Robert F.
Donat
,
Kerry
Godwin
,
Karen R.
Buttigieg
,
Julia A.
Tree
,
Julika
Radecke
,
Neil
Paterson
,
Piyada
Supasa
,
Juthathip
Mongkolsapaya
,
Gavin R.
Screaton
,
Miles W.
Carroll
,
Javier
Gilbert-Jaramillo
,
Michael L.
Knight
,
William
James
,
Raymond J.
Owens
,
James H.
Naismith
,
Alain R.
Townsend
,
Elizabeth E.
Fry
,
Yuguang
Zhao
,
Jingshan
Ren
,
David I.
Stuart
,
Kuan-Ying A.
Huang
Diamond Proposal Number(s):
[19946, 26983]
Abstract: The COVID-19 pandemic has had an unprecedented health and economic impact and there are currently no approved therapies. We have isolated an antibody, EY6A, from an individual convalescing from COVID-19 and have shown that it neutralizes SARS-CoV-2 and cross-reacts with SARS-CoV-1. EY6A Fab binds the receptor binding domain (RBD) of the viral spike glycoprotein tightly (KD of 2 nM), and a 2.6-Å-resolution crystal structure of an RBD–EY6A Fab complex identifies the highly conserved epitope, away from the ACE2 receptor binding site. Residues within this footprint are key to stabilizing the pre-fusion spike. Cryo-EM analyses of the pre-fusion spike incubated with EY6A Fab reveal a complex of the intact spike trimer with three Fabs bound and two further multimeric forms comprising the destabilized spike attached to Fab. EY6A binds what is probably a major neutralizing epitope, making it a candidate therapeutic for COVID-19.
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Jul 2020
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I03-Macromolecular Crystallography
Krios I-Titan Krios I at Diamond
|
Jiangdong
Huo
,
Audrey
Le Bas
,
Reinis R.
Ruza
,
Helen M. E.
Duyvesteyn
,
Halina
Mikolajek
,
Tomas
Malinauskas
,
Tiong Kit
Tan
,
Pramila
Rijal
,
Maud
Dumoux
,
Philip N.
Ward
,
Jingshan
Ren
,
Daming
Zhou
,
Peter J.
Harrison
,
Miriam
Weckener
,
Daniel K.
Clare
,
Vinod K.
Vogirala
,
Julika
Radecke
,
Lucile
Moynie
,
Yuguang
Zhao
,
Javier
Gilbert-Jaramillo
,
Michael L.
Knight
,
Julia A.
Tree
,
Karen R.
Buttigieg
,
Naomi
Coombes
,
Michael J.
Elmore
,
Miles W.
Carroll
,
Loic
Carrique
,
Pranav N. M.
Shah
,
William
James
,
Alain R.
Townsend
,
David I.
Stuart
,
Raymond J.
Owens
,
James H.
Naismith
Diamond Proposal Number(s):
[27031, 27051]
Open Access
Abstract: The SARS-CoV-2 virus is more transmissible than previous coronaviruses and causes a more serious illness than influenza. The SARS-CoV-2 receptor binding domain (RBD) of the spike protein binds to the human angiotensin-converting enzyme 2 (ACE2) receptor as a prelude to viral entry into the cell. Using a naive llama single-domain antibody library and PCR-based maturation, we have produced two closely related nanobodies, H11-D4 and H11-H4, that bind RBD (KD of 39 and 12 nM, respectively) and block its interaction with ACE2. Single-particle cryo-EM revealed that both nanobodies bind to all three RBDs in the spike trimer. Crystal structures of each nanobody–RBD complex revealed how both nanobodies recognize the same epitope, which partly overlaps with the ACE2 binding surface, explaining the blocking of the RBD–ACE2 interaction. Nanobody-Fc fusions showed neutralizing activity against SARS-CoV-2 (4–6 nM for H11-H4, 18 nM for H11-D4) and additive neutralization with the SARS-CoV-1/2 antibody CR3022.
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Jul 2020
|
|
I03-Macromolecular Crystallography
Krios I-Titan Krios I at Diamond
|
Jiandong
Huo
,
Yuguang
Zhao
,
Jingshan
Ren
,
Daming
Zhou
,
Helen M. E.
Duyvesteyn
,
Helen M.
Ginn
,
Loic
Carrique
,
Tomas
Malinauskas
,
Reinis R.
Ruza
,
Pranav N. M.
Shah
,
Tiong Kit
Tan
,
Pramila
Rijal
,
Naomi
Coombes
,
Kevin R.
Bewley
,
Julia A.
Tree
,
Julika
Radecke
,
Neil
Paterson
,
Piyasa
Supasa
,
Juthathip
Mongkolsapaya
,
Gavin R.
Screaton
,
Miles
Carroll
,
Alain
Townsend
,
Elizabeth E.
Fry
,
Raymond J.
Owens
,
David I.
Stuart
Diamond Proposal Number(s):
[19946, 26983]
Open Access
Abstract: There are as yet no licenced therapeutics for the COVID-19 pandemic. The causal coronavirus (SARS-CoV-2) binds host cells via a trimeric Spike whose receptor binding domain (RBD) recognises angiotensin-converting enzyme 2 (ACE2), initiating conformational changes that drive membrane fusion. We find that the monoclonal antibody CR3022 binds the RBD tightly, neutralising SARS-CoV-2 and report the crystal structure at 2.4 Å of the Fab/RBD complex. Some crystals are suitable for screening for entry-blocking inhibitors. The highly conserved, structure-stabilising, CR3022 epitope is inaccessible in the prefusion Spike, suggesting that CR3022 binding facilitates conversion to the fusion-incompetent post-fusion state. Cryo-EM analysis confirms that incubation of Spike with CR3022 Fab leads to destruction of the prefusion trimer. Presentation of this cryptic epitope in an RBD-based vaccine might advantageously focus immune responses. Binders at this epitope may be useful therapeutically, possibly in synergy with an antibody blocking receptor attachment.
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Jun 2020
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