I24-Microfocus Macromolecular Crystallography
|
Gamma
Chi
,
Larissa
Dietz
,
Haiping
Tang
,
Matthew
Snee
,
Andreea
Scacioc
,
Dong
Wang
,
Gavin
Mckinley
,
Shubhashish M. m.
Mukhopadhyay
,
Ashley C. W.
Pike
,
Rod
Chalk
,
Nicola A.
Burgess-Brown
,
Jean-Pierre
Timmermans
,
Wouter
Van Putte
,
Carol V.
Robinson
,
Katharina L.
Duerr
Open Access
Abstract: In this study, we present the structures of human urea transporters UT-A and UT-B to characterize them at molecular level and to detail the mechanism of UT-B inhibition by its selective inhibitor, UTBinh-14. High-resolution structures of both transporters establish the structural basis for the inhibitor’s selectivity to UT-B, and the identification of multiple binding sites for the inhibitor will aid with the development of drug lead molecules targeting both transporters. Our study also discovers phospholipids associating with the urea transporters by combining structural observations, native MS, and lipidomics analysis. These insights improve our understanding of urea transporter function at a molecular level and provide a blueprint for a structure-guided design of therapeutics targeting these transporters.
|
Sep 2023
|
|
I24-Microfocus Macromolecular Crystallography
|
Luke
Smithers
,
Oksana
Degtjarik
,
Dietmar
Weichert
,
Chia-Ying
Huang
,
Coilín
Boland
,
Katherine
Bowen
,
Abraham
Oluwole
,
Corinne
Lutomski
,
Carol V.
Robinson
,
Eoin M.
Scanlan
,
Meitian
Wang
,
Vincent
Olieric
,
Moran
Shalev-Benami
,
Martin
Caffrey
Diamond Proposal Number(s):
[30106, 23364]
Open Access
Abstract: Bacterial lipoproteins (BLPs) decorate the surface of membranes in the cell envelope. They function in membrane assembly and stability, as enzymes, and in transport. The final enzyme in the BLP synthesis pathway is the apolipoprotein N-acyltransferase, Lnt, which is proposed to act by a ping-pong mechanism. Here, we use x-ray crystallography and cryo–electron microscopy to chart the structural changes undergone during the progress of the enzyme through the reaction. We identify a single active site that has evolved to bind, individually and sequentially, substrates that satisfy structural and chemical criteria to position reactive parts next to the catalytic triad for reaction. This study validates the ping-pong mechanism, explains the molecular bases for Lnt’s substrate promiscuity, and should facilitate the design of antibiotics with minimal off-target effects.
|
Jun 2023
|
|
Krios II-Titan Krios II at Diamond
|
Gabriela
Dias Noske
,
Yun
Song
,
Rafaela
Sachetto Fernandes
,
Rod
Chalk
,
Haitem
Elmassoudi
,
Lizbe
Koekemoer
,
C. David
Owen
,
Tarick J.
El-Baba
,
Carol V.
Robinson
,
Glaucius
Oliva
,
Andre
Schutzer Godoy
Diamond Proposal Number(s):
[27083, 29349]
Open Access
Abstract: The main protease from SARS-CoV-2 (Mpro) is responsible for cleavage of the viral polyprotein. Mpro self-processing is called maturation, and it is crucial for enzyme dimerization and activity. Here we use C145S Mpro to study the structure and dynamics of N-terminal cleavage in solution. Native mass spectroscopy analysis shows that mixed oligomeric states are composed of cleaved and uncleaved particles, indicating that N-terminal processing is not critical for dimerization. A 3.5 Å cryo-EM structure provides details of Mpro N-terminal cleavage outside the constrains of crystal environment. We show that different classes of inhibitors shift the balance between oligomeric states. While non-covalent inhibitor MAT-POS-e194df51-1 prevents dimerization, the covalent inhibitor nirmatrelvir induces the conversion of monomers into dimers, even with intact N-termini. Our data indicates that the Mpro dimerization is triggered by induced fit due to covalent linkage during substrate processing rather than the N-terminal processing.
|
Mar 2023
|
|
I03-Macromolecular Crystallography
I04-1-Macromolecular Crystallography (fixed wavelength)
I04-Macromolecular Crystallography
I24-Microfocus Macromolecular Crystallography
|
Onno
Akkermans
,
Céline
Delloye-Bourgeois
,
Claudia
Peregrina
,
Maria
Carrasquero-Ordaz
,
Maria
Kokolaki
,
Miguel
Berbeira-Santana
,
Matthieu
Chavent
,
Florie
Reynaud
,
Ritu
Raj
,
Jon
Agirre
,
Metin
Aksu
,
Eleanor S.
White
,
Edward
Lowe
,
Dounia
Ben Amar
,
Sofia
Zaballa
,
Jiandong
Huo
,
Irene
Pakos
,
Patrick T. N.
Mccubbin
,
Davide
Comoletti
,
Raymond J.
Owens
,
Carol V.
Robinson
,
Valérie
Castellani
,
Daniel
Del Toro
,
Elena
Seiradake
Diamond Proposal Number(s):
[18069]
Open Access
Abstract: Neural migration is a critical step during brain development that requires the interactions of cell-surface guidance receptors. Cancer cells often hijack these mechanisms to disseminate. Here, we reveal crystal structures of Uncoordinated-5 receptor D (Unc5D) in complex with morphogen receptor glypican-3 (GPC3), forming an octameric glycoprotein complex. In the complex, four Unc5D molecules pack into an antiparallel bundle, flanked by four GPC3 molecules. Central glycan-glycan interactions are formed by N-linked glycans emanating from GPC3 (N241 in human) and C-mannosylated tryptophans of the Unc5D thrombospondin-like domains. MD simulations, mass spectrometry and structure-based mutants validate the crystallographic data. Anti-GPC3 nanobodies enhance or weaken Unc5-GPC3 binding and, together with mutant proteins, show that Unc5/GPC3 guide migrating pyramidal neurons in the mouse cortex, and cancer cells in an embryonic xenograft neuroblastoma model. The results demonstrate a conserved structural mechanism of cell guidance, where finely balanced Unc5-GPC3 interactions regulate cell migration.
|
Oct 2022
|
|
I02-Macromolecular Crystallography
I03-Macromolecular Crystallography
|
Herman K. H.
Fung
,
Shelley
Grimes
,
Alexis
Huet
,
Robert L.
Duda
,
Maria
Chechik
,
Joseph
Gault
,
Carol V.
Robinson
,
Roger W.
Hendrix
,
Paul J.
Jardine
,
James F.
Conway
,
Christoph G..
Baumann
,
Alfred A.
Antson
Open Access
Abstract: Many essential cellular processes rely on substrate rotation or translocation by a multi-subunit, ring-type NTPase. A large number of double-stranded DNA viruses, including tailed bacteriophages and herpes viruses, use a homomeric ring ATPase to processively translocate viral genomic DNA into procapsids during assembly. Our current understanding of viral DNA packaging comes from three archetypal bacteriophage systems: cos, pac and phi29. Detailed mechanistic understanding exists for pac and phi29, but not for cos. Here, we reconstituted in vitro a cos packaging system based on bacteriophage HK97 and provided a detailed biochemical and structural description. We used a photobleaching-based, single-molecule assay to determine the stoichiometry of the DNA-translocating ATPase large terminase. Crystal structures of the large terminase and DNA-recruiting small terminase, a first for a biochemically defined cos system, reveal mechanistic similarities between cos and pac systems. At the same time, mutational and biochemical analyses indicate a new regulatory mechanism for ATPase multimerization and coordination in the HK97 system. This work therefore establishes a framework for studying the evolutionary relationships between ATP-dependent DNA translocation machineries in double-stranded DNA viruses.
|
Aug 2022
|
|
I03-Macromolecular Crystallography
|
Diamond Proposal Number(s):
[19458, 23459]
Open Access
Abstract: β-Lactams are the most important class of antibacterials, but their use is increasingly compromised by resistance, most importantly via serine β-lactamase (SBL)-catalyzed hydrolysis. The scope of β-lactam antibacterial activity can be substantially extended by coadministration with a penicillin-derived SBL inhibitor (SBLi), i.e., the penam sulfones tazobactam and sulbactam, which are mechanism-based inhibitors working by acylation of the nucleophilic serine. The new SBLi enmetazobactam, an N-methylated tazobactam derivative, has recently completed clinical trials. Biophysical studies on the mechanism of SBL inhibition by enmetazobactam reveal that it inhibits representatives of all SBL classes without undergoing substantial scaffold fragmentation, a finding that contrasts with previous reports on SBL inhibition by tazobactam and sulbactam. We therefore reinvestigated the mechanisms of tazobactam and sulbactam using mass spectrometry under denaturing and nondenaturing conditions, X-ray crystallography, and NMR spectroscopy. The results imply that the reported extensive fragmentation of penam sulfone–derived acyl–enzyme complexes does not substantially contribute to SBL inhibition. In addition to observation of previously identified inhibitor-induced SBL modifications, the results reveal that prolonged reaction of penam sulfones with SBLs can induce dehydration of the nucleophilic serine to give a dehydroalanine residue that undergoes reaction to give a previously unobserved lysinoalanine cross-link. The results clarify the mechanisms of action of widely clinically used SBLi, reveal limitations on the interpretation of mass spectrometry studies concerning mechanisms of SBLi, and will inform the development of new SBLi working by reaction to form hydrolytically stable acyl–enzyme complexes.
|
May 2022
|
|
I04-1-Macromolecular Crystallography (fixed wavelength)
I04-Macromolecular Crystallography
|
Petra
Lukacik
,
C. David
Owen
,
Gemma
Harris
,
Jani Reddy
Bolla
,
Sarah
Picaud
,
Irfan
Alibay
,
Joanne E.
Nettleship
,
Louise E.
Bird
,
Raymond
Owens
,
Philip C.
Biggin
,
Panagis
Filippakopoulos
,
Carol V.
Robinson
,
Martin A.
Walsh
Diamond Proposal Number(s):
[4990, 5073, 4988]
Open Access
Abstract: Nontypeable Haemophilus influenzae (NTHi) is a significant pathogen in respiratory disease and otitis media. Important for NTHi survival, colonization and persistence in vivo is the Sap (sensitivity to antimicrobial peptides) ABC transporter system. Current models propose a direct role for Sap in heme and antimicrobial peptide (AMP) transport. Here, the crystal structure of SapA, the periplasmic component of Sap, in a closed, ligand bound conformation, is presented. Phylogenetic and cavity volume analysis predicts that the small, hydrophobic SapA central ligand binding cavity is most likely occupied by a hydrophobic di- or tri- peptide. The cavity is of insufficient volume to accommodate heme or folded AMPs. Crystal structures of SapA have identified surface interactions with heme and dsRNA. Heme binds SapA weakly (Kd 282 μM) through a surface exposed histidine, while the dsRNA is coordinated via residues which constitute part of a conserved motif (estimated Kd 4.4 μM). The RNA affinity falls within the range observed for characterized RNA/protein complexes. Overall, we describe in molecular-detail the interactions of SapA with heme and dsRNA and propose a role for SapA in the transport of di- or tri-peptides.
|
Oct 2021
|
|
I24-Microfocus Macromolecular Crystallography
|
Open Access
Abstract: Many of the world's most important food crops such as rice, barley and maize accumulate silicon (Si) to high levels, resulting in better plant growth and crop yields. The first step in Si accumulation is the uptake of silicic acid by the roots, a process mediated by the structurally uncharacterised NIP subfamily of aquaporins, also named metalloid porins. Here, we present the X-ray crystal structure of the archetypal NIP family member from Oryza sativa (OsNIP2;1). The OsNIP2;1 channel is closed in the crystal structure by the cytoplasmic loop D, which is known to regulate channel opening in classical plant aquaporins. The structure further reveals a novel, five-residue extracellular selectivity filter with a large diameter. Unbiased molecular dynamics simulations show a rapid opening of the channel and visualise how silicic acid interacts with the selectivity filter prior to transmembrane diffusion. Our results will enable detailed structure–function studies of metalloid porins, including the basis of their substrate selectivity.
|
Oct 2021
|
|
I03-Macromolecular Crystallography
I04-1-Macromolecular Crystallography (fixed wavelength)
I04-Macromolecular Crystallography
I24-Microfocus Macromolecular Crystallography
|
Patrick
Rabe
,
Jos J. A. G.
Kamps
,
Kyle D.
Sutherlin
,
James D. S.
Linyard
,
Pierre
Aller
,
Cindy C.
Pham
,
Mikako
Makita
,
Ian
Clifton
,
Michael A.
Mcdonough
,
Thomas M.
Leissing
,
Denis
Shutin
,
Pauline A.
Lang
,
Agata
Butryn
,
Jurgen
Brem
,
Sheraz
Gul
,
Franklin D.
Fuller
,
In-Sik
Kim
,
Mun Hon
Cheah
,
Thomas
Fransson
,
Asmit
Bhowmick
,
Iris D.
Young
,
Lee
O'Riordan
,
Aaron S.
Brewster
,
Ilaria
Pettinati
,
Margaret
Doyle
,
Yasumasa
Joti
,
Shigeki
Owada
,
Kensuke
Tono
,
Alexander
Batyuk
,
Mark S.
Hunter
,
Roberto
Alonso-Mori
,
Uwe
Bergmann
,
Robin L.
Owen
,
Nicholas K.
Sauter
,
Timothy D. W.
Claridge
,
Carol V.
Robinson
,
Vittal K.
Yachandra
,
Junko
Yano
,
Jan F.
Kern
,
Allen M.
Orville
,
Christopher J.
Schofield
Diamond Proposal Number(s):
[23459, 19458]
Open Access
Abstract: Isopenicillin N synthase (IPNS) catalyzes the unique reaction of L-δ-(α-aminoadipoyl)-L-cysteinyl-D-valine (ACV) with dioxygen giving isopenicillin N (IPN), the precursor of all natural penicillins and cephalosporins. X-ray free-electron laser studies including time-resolved crystallography and emission spectroscopy reveal how reaction of IPNS:Fe(II):ACV with dioxygen to yield an Fe(III) superoxide causes differences in active site volume and unexpected conformational changes that propagate to structurally remote regions. Combined with solution studies, the results reveal the importance of protein dynamics in regulating intermediate conformations during conversion of ACV to IPN. The results have implications for catalysis by multiple IPNS-related oxygenases, including those involved in the human hypoxic response, and highlight the power of serial femtosecond crystallography to provide insight into long-range enzyme dynamics during reactions presently impossible for nonprotein catalysts.
|
Aug 2021
|
|
Krios I-Titan Krios I at Diamond
|
Diamond Proposal Number(s):
[20223]
Open Access
Abstract: Bacterial extracellular polysaccharides (EPSs) play critical roles in virulence. Many bacteria assemble EPSs via a multi-protein “Wzx-Wzy” system, involving glycan polymerization at the outer face of the cytoplasmic/inner membrane. Gram-negative species couple polymerization with translocation across the periplasm and outer membrane and the master regulator of the system is the tyrosine autokinase, Wzc. This near atomic cryo-EM structure of dephosphorylated Wzc from E. coli shows an octameric assembly with a large central cavity formed by transmembrane helices. The tyrosine autokinase domain forms the cytoplasm region, while the periplasmic region contains small folded motifs and helical bundles. The helical bundles are essential for function, most likely through interaction with the outer membrane translocon, Wza. Autophosphorylation of the tyrosine-rich C-terminus of Wzc results in disassembly of the octamer into multiply phosphorylated monomers. We propose that the cycling between phosphorylated monomer and dephosphorylated octamer regulates glycan polymerization and translocation.
|
Jul 2021
|
|
