B23-Circular Dichroism
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Inna M.
Yasinska
,
Svetlana S.
Sakhnevych
,
Ludmila
Pavlova
,
Anette
Teo Hansen Selnø
,
Ana Maria
Teuscher Abeleira
,
Ouafa
Benlaouer
,
Isabel
Gonçalves Silva
,
Marianne
Mosimann
,
Luca
Varani
,
Marco
Bardelli
,
Rohanah
Hussain
,
Giuliano
Siligardi
,
Dietmar
Cholewa
,
Steffen M.
Berger
,
Bernhard F.
Gibbs
,
Yuri A.
Ushkaryov
,
Elizaveta
Fasler-Kan
,
Elena
Klenova
,
Vadim V.
Sumbayev
Diamond Proposal Number(s):
[20755]
Open Access
Abstract: Human cancer cells operate a variety of effective molecular and signaling mechanisms which allow them to escape host immune surveillance and thus progress the disease. We have recently reported that the immune receptor Tim-3 and its natural ligand galectin-9 are involved in the immune escape of human acute myeloid leukemia (AML) cells. These cells use the neuronal receptor latrophilin 1 (LPHN1) and its ligand fibronectin leucine rich transmembrane protein 3 (FLRT3, and possibly other ligands) to trigger the pathway. We hypothesized that the Tim-3-galectin-9 pathway may be involved in the immune escape of cancer cells of different origins. We found that studied breast tumors expressed significantly higher levels of both galectin-9 and Tim-3 compared to healthy breast tissues of the same patients and that these proteins were co-localized. Increased levels of LPHN2 and expressions of LPHN3 as well as FLRT3 were also detected in breast tumor cells. Activation of this pathway facilitated the translocation of galectin-9 onto the tumor cell surface, however no secretion of galectin-9 by tumor cells was observed. Surface-based galectin-9 was able to protect breast carcinoma cells against cytotoxic T cell-induced death. Furthermore, we found that cell lines from brain, colorectal, kidney, blood/mast cell, liver, prostate, lung, and skin cancers expressed detectable amounts of both Tim-3 and galectin-9 proteins. The majority of cell lines expressed one of the LPHN isoforms and FLRT3. We conclude that the Tim-3-galectin-9 pathway is operated by a wide range of human cancer cells and is possibly involved in prevention of anti-tumor immunity.
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Jul 2019
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B23-Circular Dichroism
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Inna M.
Yasinska
,
N. Helge
Meyer
,
Stephanie
Schlichtner
,
Rohanah
Hussain
,
Giuliano
Siligardi
,
Maxwell
Casely-Hayford
,
Walter
Fiedler
,
Jasmin
Wellbrock
,
Cloe
Desmet
,
Luigi
Calzolai
,
Luca
Varani
,
Steffen M.
Berger
,
Ulrike
Raap
,
Bernhard F.
Gibbs
,
Elizaveta
Fasler-Kan
,
Vadim V.
Sumbayev
Diamond Proposal Number(s):
[24509, 20755, 21202]
Open Access
Abstract: Acute myeloid leukemia (AML), a blood/bone marrow cancer, is a severe and often fatal malignancy. AML cells are capable of impairing the anti-cancer activities of cytotoxic lymphoid cells. This includes the inactivation of natural killer (NK) cells and killing of T lymphocytes. Here we report for the first time that V-domain Ig-containing suppressor of T cell activation (VISTA), a protein expressed by T cells, recognizes galectin-9 secreted by AML cells as a ligand. Importantly, we found that soluble VISTA released by AML cells enhances the effect of galectin-9, most likely by forming multiprotein complexes on the surface of T cells and possibly creating a molecular barrier. These events cause changes in the plasma membrane potential of T cells leading to activation of granzyme B inside cytotoxic T cells, resulting in apoptosis.
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Nov 2020
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I02-Macromolecular Crystallography
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Dennis V.
Pedersen
,
Trine A. F.
Gadeberg
,
Caroline
Thomas
,
Yong
Wang
,
Nicolas
Joram
,
Rasmus K.
Jensen
,
Sofia M. M.
Mazarakis
,
Margot
Revel
,
Carine
El Sissy
,
Steen V.
Petersen
,
Kresten
Lindorff-Larsen
,
Steffen
Thiel
,
Nick S.
Laursen
,
Véronique
Fremeaux-Bacchi
,
Gregers R.
Andersen
Diamond Proposal Number(s):
[13062]
Open Access
Abstract: Properdin (FP) is a positive regulator of the immune system stimulating the activity of the proteolytically active C3 convertase C3bBb in the alternative pathway of the complement system. Here we present two crystal structures of FP and two structures of convertase bound FP. A structural core formed by three thrombospondin repeats (TSRs) and a TB domain harbors the convertase binding site in FP that mainly interacts with C3b. Stabilization of the interaction between the C3b C-terminus and the MIDAS bound Mg2+ in the Bb protease by FP TSR5 is proposed to underlie FP convertase stabilization. Intermolecular contacts between FP and the convertase subunits suggested by the structure were confirmed by binding experiments. FP is shown to inhibit C3b degradation by FI due to a direct competition for a common binding site on C3b. FP oligomers are held together by two sets of intermolecular contacts, where the first is formed by the TB domain from one FP molecule and TSR4 from another. The second and largest interface is formed by TSR1 and TSR6 from the same two FP molecules. Flexibility at four hinges between thrombospondin repeats is suggested to enable the oligomeric, polydisperse, and extended architecture of FP. Our structures rationalize the effects of mutations associated with FP deficiencies and provide a structural basis for the analysis of FP function in convertases and its possible role in pattern recognition.
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Aug 2019
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I02-Macromolecular Crystallography
I03-Macromolecular Crystallography
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Ralph
Adams
,
Callum
Joyce
,
Mikhail
Kuravskiy
,
Katriona
Harrison
,
Zainab
Ahdash
,
Matthew
Balmforth
,
Kelda
Chia
,
Cinzia
Marceddu
,
Matthew
Coates
,
James
Snowden
,
Emmanuel
Goursaud
,
Karelle
Ménochet
,
Jean
Van Den Elsen
,
Richard J.
Payne
,
Alastair D. G.
Lawson
,
Anthony
Scott-Tucker
,
Alex
Macpherson
Open Access
Abstract: Background: Serum albumin binding is an established mechanism to extend the serum half-life of antibody fragments and peptides. The cysteine rich knob domains, isolated from bovine antibody ultralong CDRH3, are the smallest single chain antibody fragments described to date and versatile tools for protein engineering.
Methods: Here, we used phage display of bovine immune material to derive knob domains against human and rodent serum albumins. These were used to engineer bispecific Fab fragments, by using the framework III loop as a site for knob domain insertion.
Results: By this route, neutralisation of the canonical antigen (TNFα) was retained but extended pharmacokinetics in-vivo were achieved through albumin binding. Structural characterisation revealed correct folding of the knob domain and identified broadly common but non-cross-reactive epitopes. Additionally, we show that these albumin binding knob domains can be chemically synthesised to achieve dual IL-17A neutralisation and albumin binding in a single chemical entity.
Conclusions: This study enables antibody and chemical engineering from bovine immune material, via an accessible discovery platform.
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May 2023
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I03-Macromolecular Crystallography
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Dorien
De Vlieger
,
Katja
Hoffmann
,
Inge
Van Molle
,
Wim
Nerinckx
,
Lien
Van Hoecke
,
Marlies
Ballegeer
,
Sarah
Creytens
,
Han
Remaut
,
Hartmut
Hengel
,
Bert
Schepens
,
Xavier
Saelens
Open Access
Abstract: Lower respiratory tract infections, such as infections caused by influenza A viruses, are a constant threat for public health. Antivirals are indispensable to control disease caused by epidemic as well as pandemic influenza A. We developed a novel anti-influenza A virus approach based on an engineered single-domain antibody (VHH) construct that can selectively recruit innate immune cells to the sites of virus replication. This protective construct comprises two VHHs. One VHH binds with nanomolar affinity to the conserved influenza A matrix protein 2 (M2) ectodomain (M2e). Co-crystal structure analysis revealed that the complementarity determining regions 2 and 3 of this VHH embrace M2e. The second selected VHH specifically binds to the mouse Fcγ Receptor IV (FcγRIV) and was genetically fused to the M2e-specific VHH, which resulted in a bi-specific VHH-based construct that could be efficiently expressed in Pichia pastoris. In the presence of M2 expressing or influenza A virus-infected target cells, this single domain antibody construct selectively activated the mouse FcγRIV. Moreover, intranasal delivery of this bispecific FcγRIV-engaging VHH construct protected wild type but not FcγRIV−/− mice against challenge with an H3N2 influenza virus. These results provide proof of concept that VHHs directed against a surface exposed viral antigen can be readily armed with effector functions that trigger protective antiviral activity beyond direct virus neutralization.
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Dec 2019
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I03-Macromolecular Crystallography
I04-1-Macromolecular Crystallography (fixed wavelength)
I24-Microfocus Macromolecular Crystallography
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David K.
Cole
,
Anna
Fuller
,
Garry
Dolton
,
Efthalia
Zervoudi
,
Mateusz
Legut
,
Kim
Miles
,
Lori
Blanchfield
,
Florian
Madura
,
Christopher J.
Holland
,
Anna M.
Bulek
,
John S.
Bridgeman
,
John J.
Miles
,
Andrea J. A.
Schauenburg
,
Konrad
Beck
,
Brian D.
Evavold
,
Pierre
Rizkallah
,
Andrew K.
Sewell
Diamond Proposal Number(s):
[4532, 6232]
Abstract: Serial accumulation of mutations to fixation in the SLYNTVATL (SL9) immunodominant, HIV p17 Gag-derived, HLA A2-restricted cytotoxic T lymphocyte epitope produce the SLFNTIAVL triple mutant “ultimate” escape variant. These mutations in solvent-exposed residues are believed to interfere with TCR recognition, although confirmation has awaited structural verification. Here, we solved a TCR co-complex structure with SL9 and the triple escape mutant to determine the mechanism of immune escape in this eminent system. We show that, in contrast to prevailing hypotheses, the main TCR contact residue is 4N and the dominant mechanism of escape is not via lack of TCR engagement. Instead, mutation of solvent-exposed residues in the peptide destabilise the peptide–HLA and reduce peptide density at the cell surface. These results highlight the extraordinary lengths that HIV employs to evade detection by high-affinity TCRs with a broad peptide-binding footprint and necessitate re-evaluation of this exemplar model of HIV TCR escape.
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Nov 2017
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I04-1-Macromolecular Crystallography (fixed wavelength)
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Christopher J.
Holland
,
Bruce J.
Maclachlan
,
Valentina
Bianchi
,
Sophie J.
Hesketh
,
Richard
Morgan
,
Owen
Vickery
,
Anna M.
Bulek
,
Anna
Fuller
,
Andrew
Godkin
,
Andrew K.
Sewell
,
Pierre
Rizkallah
,
Stephen
Wells
,
David
Cole
Open Access
Abstract: T-cell immunity is controlled by T cell receptor (TCR) binding to peptide major histocompatibility complexes (pMHCs). The nature of the interaction between these two proteins has been the subject of many investigations because of its central role in immunity against pathogens, cancer, in autoimmunity, and during organ transplant rejection. Crystal structures comparing unbound and pMHC-bound TCRs have revealed flexibility at the interaction interface, particularly from the perspective of the TCR. However, crystal structures represent only a snapshot of protein conformation that could be influenced through biologically irrelevant crystal lattice contacts and other factors. Here, we solved the structures of three unbound TCRs from multiple crystals. Superposition of identical TCR structures from different crystals revealed some conformation differences of up to 5 Å in individual complementarity determining region (CDR) loops that are similar to those that have previously been attributed to antigen engagement. We then used a combination of rigidity analysis and simulations of protein motion to reveal the theoretical potential of TCR CDR loop flexibility in unbound state. These simulations of protein motion support the notion that crystal structures may only offer an artifactual indication of TCR flexibility, influenced by crystallization conditions and crystal packing that is inconsistent with the theoretical potential of intrinsic TCR motions.
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Apr 2018
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I04-1-Macromolecular Crystallography (fixed wavelength)
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José T.
Moreira-Filho
,
Arthur C.
Silva
,
Rafael F.
Dantas
,
Barbara F.
Gomes
,
Lauro R.
De Souza Neto
,
Jose
Brandao-Neto
,
Raymond J.
Owens
,
Nicholas
Furnham
,
Bruno J.
Neves
,
Floriano P.
Silva-Junior
,
Carolina H.
Andrade
Diamond Proposal Number(s):
[16978]
Open Access
Abstract: Schistosomiasis is a parasitic disease caused by trematode worms of the genus Schistosoma and affects over 200 million people worldwide. The control and treatment of this neglected tropical disease is based on a single drug, praziquantel, which raises concerns about the development of drug resistance. This, and the lack of efficacy of praziquantel against juvenile worms, highlights the urgency for new antischistosomal therapies. In this review we focus on innovative approaches to the identification of antischistosomal drug candidates, including the use of automated assays, fragment-based screening, computer-aided and artificial intelligence-based computational methods. We highlight the current developments that may contribute to optimizing research outputs and lead to more effective drugs for this highly prevalent disease, in a more cost-effective drug discovery endeavor.
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May 2021
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I04-Macromolecular Crystallography
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Ayla A.
Wahid
,
Rhys W.
Dunphy
,
Alex
Macpherson
,
Beth G.
Gibson
,
Liudmila
Kulik
,
Kevin
Whale
,
Catherine
Back
,
Thomas M.
Hallam
,
Bayan
Alkhawaja
,
Rebecca L.
Martin
,
Ingrid
Meschede
,
Maisem
Laabei
,
Alastair D. G.
Lawson
,
V. Michael
Holers
,
Andrew G.
Watts
,
Susan J.
Crennell
,
Claire L.
Harris
,
Kevin J.
Marchbank
,
Jean M. H.
Van Den Elsen
Diamond Proposal Number(s):
[17212]
Open Access
Abstract: Cleavage of C3 to C3a and C3b plays a central role in the generation of complement-mediated defences. Although the thioester-mediated surface deposition of C3b has been well-studied, fluid phase dimers of C3 fragments remain largely unexplored. Here we show C3 cleavage results in the spontaneous formation of C3b dimers and present the first X-ray crystal structure of a disulphide-linked human C3d dimer. Binding studies reveal these dimers are capable of crosslinking complement receptor 2 and preliminary cell-based analyses suggest they could modulate B cell activation to influence tolerogenic pathways. Altogether, insights into the physiologically-relevant functions of C3d(g) dimers gained from our findings will pave the way to enhancing our understanding surrounding the importance of complement in the fluid phase and could inform the design of novel therapies for immune system disorders in the future.
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Aug 2021
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I04-Macromolecular Crystallography
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Diamond Proposal Number(s):
[23269]
Open Access
Abstract: Staphylococcus aureus is an opportunistic pathogen that is able to thwart an effective host immune response by producing a range of immune evasion molecules, including S. aureus binder of IgG (Sbi) which interacts directly with the central complement component C3, its fragments and associated regulators. Recently we reported the first structure of a disulfide-linked human C3d17C dimer and highlighted its potential role in modulating B-cell activation. Here we present an X-ray crystal structure of a disulfide-linked human C3d17C dimer, which undergoes a structurally stabilising N-terminal 3D domain swap when in complex with Sbi. These structural studies, in combination with circular dichroism and fluorescence spectroscopic analyses, reveal the mechanism underpinning this unique helix swap event and could explain the origins of a previously discovered N-terminally truncated C3dg dimer isolated from rat serum. Overall, our study unveils a novel staphylococcal complement evasion mechanism which enables the pathogen to harness the ability of dimeric C3d to modulate B-cell activation.
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May 2022
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