1
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Krah A, Vogelaar T, de Jong SI, Claridge JK, Bond PJ, McMillan DGG. ATP binding by an F 1F o ATP synthase ε subunit is pH dependent, suggesting a diversity of ε subunit functional regulation in bacteria. Front Mol Biosci 2023; 10:1059673. [PMID: 36923639 PMCID: PMC10010621 DOI: 10.3389/fmolb.2023.1059673] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Accepted: 01/03/2023] [Indexed: 03/03/2023] Open
Abstract
It is a conjecture that the ε subunit regulates ATP hydrolytic function of the F1Fo ATP synthase in bacteria. This has been proposed by the ε subunit taking an extended conformation, with a terminal helix probing into the central architecture of the hexameric catalytic domain, preventing ATP hydrolysis. The ε subunit takes a contracted conformation when bound to ATP, thus would not interfere with catalysis. A recent crystallographic study has disputed this; the Caldalkalibacillus thermarum TA2.A1 F1Fo ATP synthase cannot natively hydrolyse ATP, yet studies have demonstrated that the loss of the ε subunit terminal helix results in an ATP synthase capable of ATP hydrolysis, supporting ε subunit function. Analysis of sequence and crystallographic data of the C. thermarum F1Fo ATP synthase revealed two unique histidine residues. Molecular dynamics simulations suggested that the protonation state of these residues may influence ATP binding site stability. Yet these residues lie outside the ATP/Mg2+ binding site of the ε subunit. We then probed the effect of pH on the ATP binding affinity of the ε subunit from the C. thermarum F1Fo ATP synthase at various physiologically relevant pH values. We show that binding affinity changes 5.9 fold between pH 7.0, where binding is weakest, to pH 8.5 where it is strongest. Since the C. thermarum cytoplasm is pH 8.0 when it grows optimally, this correlates to the ε subunit being down due to ATP/Mg2+ affinity, and not being involved in blocking ATP hydrolysis. Here, we have experimentally correlated that the pH of the bacterial cytoplasm is of critical importance for ε subunit ATP affinity regulated by second-shell residues thus the function of the ε subunit changes with growth conditions.
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Affiliation(s)
- Alexander Krah
- Korea Institute for Advanced Study, School of Computational Sciences, Seoul, South Korea.,Bioinformatics Institute, Agency for Science, Technology and Research (ASTAR), Singapore, Singapore
| | - Timothy Vogelaar
- Department of Biotechnology, Delft University of Technology, Delft, Netherlands
| | - Sam I de Jong
- Department of Biotechnology, Delft University of Technology, Delft, Netherlands
| | - Jolyon K Claridge
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand
| | - Peter J Bond
- Bioinformatics Institute, Agency for Science, Technology and Research (ASTAR), Singapore, Singapore.,Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - Duncan G G McMillan
- Department of Biotechnology, Delft University of Technology, Delft, Netherlands.,School of Fundamental Sciences, Massey University, Palmerston North, New Zealand
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2
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Mohd-Kipli F, Claridge JK, Habjanič J, Jiang A, Schnell JR. Conformational triggers associated with influenza matrix protein 1 polymerization. J Biol Chem 2021; 296:100316. [PMID: 33516724 PMCID: PMC7949140 DOI: 10.1016/j.jbc.2021.100316] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 12/28/2020] [Accepted: 01/19/2021] [Indexed: 11/26/2022] Open
Abstract
A central role for the influenza matrix protein 1 (M1) is to form a polymeric coat on the inner leaflet of the host membrane that ultimately provides shape and stability to the virion. M1 polymerizes upon binding membranes, but triggers for conversion of M1 from a water-soluble component of the nucleus and cytosol into an oligomer at the membrane surface are unknown. While full-length M1 is required for virus viability, the N-terminal domain (M1NT) retains membrane binding and pH-dependent oligomerization. We studied the structural plasticity and oligomerization of M1NT in solution using NMR spectroscopy. We show that the isolated domain can be induced by sterol-containing compounds to undergo a conformational change and self-associate in a pH-dependent manner consistent with the stacked dimer oligomeric interface. Surface-exposed residues at one of the stacked dimer interfaces are most sensitive to sterols. Several perturbed residues are at the interface between the N-terminal subdomains and are also perturbed by changes in pH. The effects of sterols appear to be indirect and most likely mediated by reduction in water activity. The local changes are centered on strictly conserved residues and consistent with a priming of the N-terminal domain for polymerization. We hypothesize that M1NT is sensitive to changes in the aqueous environment and that this sensitivity is part of a mechanism for restricting polymerization to the membrane surface. Structural models combined with information from chemical shift perturbations indicate mechanisms by which conformational changes can be transmitted from one polymerization interface to the other.
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Affiliation(s)
- Faiz Mohd-Kipli
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom; Faculty of Science, Universiti Brunei Darussalam, Gadong, Brunei Darussalam
| | - Jolyon K Claridge
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Jelena Habjanič
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Alex Jiang
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Jason R Schnell
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom.
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3
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Claridge JK, Mohd-Kipli F, Florea A, Gate T, Schnell JR. pH-dependent secondary structure propensity of the influenza A virus M2 cytoplasmic tail. Biomol NMR Assign 2020; 14:157-161. [PMID: 32157574 PMCID: PMC7069904 DOI: 10.1007/s12104-020-09937-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Accepted: 03/04/2020] [Indexed: 06/10/2023]
Abstract
The cytoplasmic C-terminal tail of the matrix protein 2 (M2) from influenza A virus has a well conserved sequence and is involved in interactions with several host proteins as well as the influenza matrix protein 1 (M1). Whereas the transmembrane domain of M2 has been well characterised structurally and functionally, high resolution information about the distal cytoplasmic tail is lacking. Here we report the chemical shifts of the cytoplasmic tail of M2 and the chemical shift perturbations at low pH and in the presence of membrane mimetics. The cytoplasmic tail residues are mostly disordered but an extended backbone conformation is adopted by the LC3 binding motif and the putative M1 interaction site has partial helical content with a small pH-dependence. The chemical shift assignments provide a basis for further investigations into interactions of the M2 cytoplasmic tail with viral and host cell factors.
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Affiliation(s)
- Jolyon K Claridge
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK
| | - Faiz Mohd-Kipli
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK
| | - Andrei Florea
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK
| | - Thomas Gate
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK
| | - Jason R Schnell
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK.
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4
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Oestringer BP, Bolivar JH, Claridge JK, Almanea L, Chipot C, Dehez F, Holzmann N, Schnell JR, Zitzmann N. Hepatitis C virus sequence divergence preserves p7 viroporin structural and dynamic features. Sci Rep 2019; 9:8383. [PMID: 31182749 PMCID: PMC6557816 DOI: 10.1038/s41598-019-44413-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Accepted: 05/10/2019] [Indexed: 12/31/2022] Open
Abstract
The hepatitis C virus (HCV) viroporin p7 oligomerizes to form ion channels, which are required for the assembly and secretion of infectious viruses. The 63-amino acid p7 monomer has two putative transmembrane domains connected by a cytosolic loop, and has both N- and C- termini exposed to the endoplasmic reticulum (ER) lumen. NMR studies have indicated differences between p7 structures of distantly related HCV genotypes. A critical question is whether these differences arise from the high sequence variation between the different isolates and if so, how the divergent structures can support similar biological functions. Here, we present a side-by-side characterization of p7 derived from genotype 1b (isolate J4) in the detergent 6-cyclohexyl-1-hexylphosphocholine (Cyclofos-6) and p7 derived from genotype 5a (isolate EUH1480) in n-dodecylphosphocholine (DPC). The 5a isolate p7 in conditions previously associated with a disputed oligomeric form exhibits secondary structure, dynamics, and solvent accessibility broadly like those of the monomeric 1b isolate p7. The largest differences occur at the start of the second transmembrane domain, which is destabilized in the 5a isolate. The results show a broad consensus among the p7 variants that have been studied under a range of different conditions and indicate that distantly related HCVs preserve key features of structure and dynamics.
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Affiliation(s)
- Benjamin P Oestringer
- Oxford Glycobiology Institute, Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, United Kingdom.,Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, United Kingdom.,Immunocore Limited, 101 Park Drive, Milton Park, Abingdon, Oxon, OX14 4RY, United Kingdom
| | - Juan H Bolivar
- Oxford Glycobiology Institute, Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, United Kingdom
| | - Jolyon K Claridge
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, United Kingdom.,Structural Biology Brussels, Vrije Universiteit Brussel, Pleinlaan 2, 1050, Brussels, Belgium.,Structural and Molecular Microbiology, Structural Biology Research Center, VIB, Pleinlaan 2, 1050, Brussels, Belgium
| | - Latifah Almanea
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, United Kingdom
| | - Chris Chipot
- Laboratoire International Associé CNRS-University of Illinois at Urbana Champaign, Université de Lorraine, BP 70239, 54506, Vandœuvre-lès-Nancy, France.,Department of Physics, University of Illinois at Urbana-Champaign, 1110 West Green Street, Urbana, Illinois, 61801, United States
| | - François Dehez
- Laboratoire International Associé CNRS-University of Illinois at Urbana Champaign, Université de Lorraine, BP 70239, 54506, Vandœuvre-lès-Nancy, France
| | - Nicole Holzmann
- Laboratoire International Associé CNRS-University of Illinois at Urbana Champaign, Université de Lorraine, BP 70239, 54506, Vandœuvre-lès-Nancy, France
| | - Jason R Schnell
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, United Kingdom.
| | - Nicole Zitzmann
- Oxford Glycobiology Institute, Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, United Kingdom.
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5
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Dixon EV, Claridge JK, Harvey DJ, Baruah K, Yu X, Vesiljevic S, Mattick S, Pritchard LK, Krishna B, Scanlan CN, Schnell JR, Higgins MK, Zitzmann N, Crispin M. Fragments of bacterial endoglycosidase s and immunoglobulin g reveal subdomains of each that contribute to deglycosylation. J Biol Chem 2014; 289:13876-89. [PMID: 24668806 PMCID: PMC4022860 DOI: 10.1074/jbc.m113.532812] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Endoglycosidase S (EndoS) is a glycoside-hydrolase secreted by the bacterium Streptococcus pyogenes. EndoS preferentially hydrolyzes the N-linked glycans from the Fc region of IgG during infection. This hydrolysis impedes Fc functionality and contributes to the immune evasion strategy of S. pyogenes. Here, we investigate the mechanism of human serum IgG deactivation by EndoS. We expressed fragments of IgG1 and demonstrated that EndoS was catalytically active against all of them including the isolated CH2 domain of the Fc domain. Similarly, we sought to investigate which domains within EndoS could contribute to activity. Bioinformatics analysis of the domain organization of EndoS confirmed the previous predictions of a chitinase domain and leucine-rich repeat but also revealed a putative carbohydrate binding module (CBM) followed by a C-terminal region. Using expressed fragments of EndoS, circular dichroism of the isolated CBM, and a CBM-C-terminal region fusion revealed folded domains dominated by β sheet and α helical structure, respectively. Nuclear magnetic resonance analysis of the CBM with monosaccharides was suggestive of carbohydrate binding functionality. Functional analysis of truncations of EndoS revealed that, whereas the C-terminal of EndoS is dispensable for activity, its deletion impedes the hydrolysis of IgG glycans.
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Affiliation(s)
- Emma V Dixon
- From the Oxford Glycobiology Institute, Department of Biochemistry and
| | - Jolyon K Claridge
- Department of Biochemistry, University of Oxford, South Parks Rd., Oxford OX1 3QU, United Kingdom, and
| | - David J Harvey
- From the Oxford Glycobiology Institute, Department of Biochemistry and School of Life Sciences, University of Warwick, Gibbet Hill Campus, Coventry, CV4 7AL, United Kingdom
| | - Kavitha Baruah
- From the Oxford Glycobiology Institute, Department of Biochemistry and
| | - Xiaojie Yu
- From the Oxford Glycobiology Institute, Department of Biochemistry and
| | | | - Susan Mattick
- From the Oxford Glycobiology Institute, Department of Biochemistry and
| | - Laura K Pritchard
- From the Oxford Glycobiology Institute, Department of Biochemistry and
| | - Benjamin Krishna
- From the Oxford Glycobiology Institute, Department of Biochemistry and
| | | | - Jason R Schnell
- Department of Biochemistry, University of Oxford, South Parks Rd., Oxford OX1 3QU, United Kingdom, and
| | - Matthew K Higgins
- Department of Biochemistry, University of Oxford, South Parks Rd., Oxford OX1 3QU, United Kingdom, and
| | - Nicole Zitzmann
- From the Oxford Glycobiology Institute, Department of Biochemistry and
| | - Max Crispin
- From the Oxford Glycobiology Institute, Department of Biochemistry and
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6
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Claridge JK, Aittoniemi J, Cooper DM, Schnell JR. Isotropic bicelles stabilize the juxtamembrane region of the influenza M2 protein for solution NMR studies. Biochemistry 2013; 52:8420-9. [PMID: 24168642 DOI: 10.1021/bi401035m] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The protein M2 from influenza is a tetrameric membrane protein with several roles in the viral life cycle. The transmembrane helix (TMH) of M2 has proton channel activity that is required for unpackaging the viral genome. Additionally a C-terminal juxtamembrane region includes an amphipathic helix (APH) important for virus budding and scission. The APH interacts with membranes and is required for M2 localization to the site of viral budding. As a step toward obtaining high resolution information on the structure and lipid interactions of the M2 APH, we sought to develop a fast tumbling bicelle system, which would make studies of M2 in a membrane-like environment by solution NMR possible. Since M2 is highly sensitive to the solubilizing environment, an M2 construct containing the APH was studied under micelle and bicelle conditions while maintaining the same detergent and lipid headgroup chemistry to facilitate interpretation of the spectroscopic results. The sequence from a human H1N1 "swine flu" isolate was used to design an M2 construct (swM2) similar in amino acid sequence to currently circulating viruses. Comparison of swM2 solubilized in either the diacyl detergent 1,2-dihexanoyl-sn-glycero-3-phosphocholine (DHPC) or a mixture of DHPC and the lipid 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) (q = 0.4) indicated that the largest changes were a decrease in helicity at the N-terminus of the TMH and a decrease in dynamics for the juxtamembrane linker residues connecting the TMH and the APH. Whereas the linker region is very dynamic and the amide protons are rapidly exchanged with water protons in micelles, the dynamics and water exchange are largely suppressed in the presence of lipid. Chemical shift changes and relaxation measurements were consistent with an overall stabilization of the linker region, with only modest changes in conformation or environment of the APH itself. Such changes are consistent with differences observed in structures of M2 in lipid bilayers and detergent micelles, indicating that the bicelle system provides a more membrane-like environment.
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Affiliation(s)
- Jolyon K Claridge
- Department of Biochemistry, University of Oxford , South Parks Road, Oxford, OX1 3QU, United Kingdom
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7
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Abstract
Advances in solution nuclear magnetic resonance (NMR) methodology that enable studies of very large proteins have also paved the way for studies of membrane proteins that behave like large proteins due to the added weight of surfactants. Solution NMR has been used to determine the high-resolution structures of several small, membrane proteins dissolved in detergent micelles and small bicelles. However, the usual difficulties with membrane proteins in producing, purifying, and stabilizing the proteins away from native membranes remain, requiring intensive screening efforts. Low levels of heterologous expression can be the most detrimental aspect to studying membrane proteins. This is exacerbated for NMR studies because of the costs of isotopically enriched media. Thus, solution NMR studies have tended to focus on relatively small, membrane proteins that can be expressed into inclusion bodies and refolded. Here, we describe the methods used to produce, purify, and refold the proton channel M2 into detergent micelles, and the procedures used to determine chemical shift assignments and the atomic level structure of the closed form of the homotetrameric channel.
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8
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Venugopal H, Edwards PJB, Schwalbe M, Claridge JK, Libich DS, Stepper J, Loo T, Patchett ML, Norris GE, Pascal SM. Structural, Dynamic, and Chemical Characterization of a Novel S-Glycosylated Bacteriocin. Biochemistry 2011; 50:2748-55. [DOI: 10.1021/bi200217u] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Hariprasad Venugopal
- Institute of Fundamental Sciences, Massey University, Palmerston North, New Zealand
| | | | - Martin Schwalbe
- Institute of Fundamental Sciences, Massey University, Palmerston North, New Zealand
| | - Jolyon K. Claridge
- Institute of Fundamental Sciences, Massey University, Palmerston North, New Zealand
| | - David S. Libich
- Institute of Fundamental Sciences, Massey University, Palmerston North, New Zealand
| | - Judith Stepper
- Institute of Molecular Biosciences, Massey University, Palmerston North, New Zealand
| | - Trevor Loo
- Institute of Molecular Biosciences, Massey University, Palmerston North, New Zealand
| | - Mark L. Patchett
- Institute of Molecular Biosciences, Massey University, Palmerston North, New Zealand
| | - Gillian E. Norris
- Institute of Molecular Biosciences, Massey University, Palmerston North, New Zealand
| | - Steven M. Pascal
- Institute of Fundamental Sciences, Massey University, Palmerston North, New Zealand
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9
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Schwalbe M, Dutta K, Libich DS, Venugopal H, Claridge JK, Gell DA, Mackay JP, Edwards PJB, Pascal SM. Two-state conformational equilibrium in the Par-4 leucine zipper domain. Proteins 2010; 78:2433-49. [PMID: 20602362 DOI: 10.1002/prot.22752] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Prostate apoptosis response factor-4 (Par-4) is a pro-apoptotic and tumor-suppressive protein. A highly conserved heptad repeat sequence at the Par-4 C-terminus suggests the presence of a leucine zipper (LZ). This C-terminal region is essential for Par-4 self-association and interaction with various effector proteins. We have used nuclear magnetic resonance (NMR) spectroscopy to fully assign the chemical shift resonances of a peptide comprising the LZ domain of Par-4 at neutral pH. Further, we have investigated the properties of the Par-4 LZ domain and two point mutants under a variety of conditions using NMR, circular dichroism (CD), light scattering, and bioinformatics. Results indicate an environment-dependent conformational equilibrium between a partially ordered monomer (POM) and a predominantly coiled coil dimer (CCD). The combination of techniques used allows the time scales of the equilibrium to be probed and also helps to identify features of the amino acid sequence that may influence the equilibrium.
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Affiliation(s)
- Martin Schwalbe
- Centre for Structural Biology, Institute of Fundamental Sciences, Massey University, Palmerston North, New Zealand
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10
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Headey SJ, MacAskill UK, Wright MA, Claridge JK, Edwards PJB, Farley PC, Christeller JT, Laing WA, Pascal SM. Solution structure of the squash aspartic acid proteinase inhibitor (SQAPI) and mutational analysis of pepsin inhibition. J Biol Chem 2010; 285:27019-27025. [PMID: 20538608 DOI: 10.1074/jbc.m110.137018] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The squash aspartic acid proteinase inhibitor (SQAPI), a proteinaceous proteinase inhibitor from squash, is an effective inhibitor of a range of aspartic proteinases. Proteinaceous aspartic proteinase inhibitors are rare in nature. The only other example in plants probably evolved from a precursor serine proteinase inhibitor. Earlier work based on sequence homology modeling suggested SQAPI evolved from an ancestral cystatin. In this work, we determined the solution structure of SQAPI using NMR and show that SQAPI shares the same fold as a plant cystatin. The structure is characterized by a four-strand anti-parallel beta-sheet gripping an alpha-helix in an analogous manner to fingers of a hand gripping a tennis racquet. Truncation and site-specific mutagenesis revealed that the unstructured N terminus and the loop connecting beta-strands 1 and 2 are important for pepsin inhibition, but the loop connecting strands 3 and 4 is not. Using ambiguous restraints based on the mutagenesis results, SQAPI was then docked computationally to pepsin. The resulting model places the N-terminal strand of SQAPI in the S' side of the substrate binding cleft, whereas the first SQAPI loop binds on the S side of the cleft. The backbone of SQAPI does not interact with the pepsin catalytic Asp(32)-Asp(215) diad, thus avoiding cleavage. The data show that SQAPI does share homologous structural elements with cystatin and appears to retain a similar protease inhibitory mechanism despite its different target. This strongly supports our hypothesis that SQAPI evolved from an ancestral cystatin.
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Affiliation(s)
- Stephen J Headey
- Institute of Fundamental Sciences, Massey University, Palmerston North 4442, New Zealand
| | - Ursula K MacAskill
- Institute of Molecular Biosciences, Massey University, Palmerston North 4442, New Zealand
| | - Michele A Wright
- The New Zealand Institute for Plant & Food Research Limited, Auckland 1142, New Zealand
| | - Jolyon K Claridge
- Institute of Fundamental Sciences, Massey University, Palmerston North 4442, New Zealand
| | - Patrick J B Edwards
- Institute of Fundamental Sciences, Massey University, Palmerston North 4442, New Zealand
| | - Peter C Farley
- Institute of Molecular Biosciences, Massey University, Palmerston North 4442, New Zealand
| | - John T Christeller
- The New Zealand Institute for Plant & Food Research Limited, Palmerston North 4442, New Zealand
| | - William A Laing
- The New Zealand Institute for Plant & Food Research Limited, Auckland 1142, New Zealand.
| | - Steven M Pascal
- Institute of Fundamental Sciences, Massey University, Palmerston North 4442, New Zealand.
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11
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Claridge JK, Headey SJ, Chow JYH, Schwalbe M, Edwards PJ, Jeffries CM, Venugopal H, Trewhella J, Pascal SM. A picornaviral loop-to-loop replication complex. J Struct Biol 2009; 166:251-62. [PMID: 19268541 PMCID: PMC7172786 DOI: 10.1016/j.jsb.2009.02.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2008] [Revised: 01/30/2009] [Accepted: 02/21/2009] [Indexed: 11/28/2022]
Abstract
Picornaviruses replicate their RNA genomes through a highly conserved mechanism that involves an interaction between the principal viral protease (3C(pro)) and the 5'-UTR region of the viral genome. The 3C(pro) catalytic site is the target of numerous replication inhibitors. This paper describes the first structural model of a complex between a picornaviral 3C(pro) and a region of the 5'-UTR, stem-loop D (SLD). Using human rhinovirus as a model system, we have combined NMR contact information, small-angle X-ray scattering (SAXS) data, and previous mutagenesis results to determine the shape, position and relative orientation of the 3C(pro) and SLD components. The results clearly identify a 1:1 binding stoichiometry, with pronounced loops from each molecule providing the key binding determinants for the interaction. Binding between SLD and 3C(pro) induces structural changes in the proteolytic active site that is positioned on the opposite side of the protease relative to the RNA/protein interface, suggesting that subtle conformational changes affecting catalytic activity are relayed through the protein.
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Affiliation(s)
- Jolyon K Claridge
- Institute of Fundamental Sciences, Massey University, Private Bag 11222, Palmerston North 4442, New Zealand
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12
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Libich DS, Schwalbe M, Kate S, Venugopal H, Claridge JK, Edwards PJB, Dutta K, Pascal SM. Intrinsic disorder and coiled-coil formation in prostate apoptosis response factor 4. FEBS J 2009; 276:3710-28. [PMID: 19490121 DOI: 10.1111/j.1742-4658.2009.07087.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Prostate apoptosis response factor-4 (Par-4) is an ubiquitously expressed pro-apoptotic and tumour suppressive protein that can both activate cell-death mechanisms and inhibit pro-survival factors. Par-4 contains a highly conserved coiled-coil region that serves as the primary recognition domain for a large number of binding partners. Par-4 is also tightly regulated by the aforementioned binding partners and by post-translational modifications. Biophysical data obtained in the present study indicate that Par-4 primarily comprises an intrinsically disordered protein. Bioinformatic analysis of the highly conserved Par-4 reveals low sequence complexity and enrichment in polar and charged amino acids. The high proteolytic susceptibility and an increased hydrodynamic radius are consistent with a largely extended structure in solution. Spectroscopic measurements using CD and NMR also reveal characteristic features of intrinsic disorder. Under physiological conditions, the data obtained show that Par-4 self-associates via the C-terminal domain, forming a coiled-coil. Interruption of self-association by urea also resulted in loss of secondary structure. These results are consistent with the stabilization of the coiled-coil motif through an intramolecular association.
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Affiliation(s)
- David S Libich
- Centre for Structural Biology, Institute of Fundamental Sciences, Massey University, Palmerston North, New Zealand.
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13
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Headey SJ, Huang H, Claridge JK, Soares GA, Dutta K, Schwalbe M, Yang D, Pascal SM. NMR structure of stem-loop D from human rhinovirus-14. RNA 2007; 13:351-60. [PMID: 17194719 PMCID: PMC1800519 DOI: 10.1261/rna.313707] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2006] [Accepted: 10/31/2006] [Indexed: 05/13/2023]
Abstract
The 5'-cloverleaf of the picornavirus RNA genome is essential for the assembly of a ribonucleoprotein replication complex. Stem-loop D (SLD) of the cloverleaf is the recognition site for the multifunctional viral protein 3Cpro. This protein is the principal viral protease, and its interaction with SLD also helps to position the viral RNA-dependent RNA polymerase (3Dpol) for replication. Human rhinovirus-14 (HRV-14) is distinct from the majority of picornaviruses in that its SLD forms a cUAUg triloop instead of the more common uYACGg tetraloop. This difference appears to be functionally significant, as 3Cpro from tetraloop-containing viruses cannot bind the HRV-14 SLD. We have determined the solution structure of the HRV-14 SLD using NMR spectroscopy. The structure is predominantly an A-form helix, but with a central pyrimidine-pyrimidine base-paired region and a significantly widened major groove. The stabilizing hydrogen bonding present in the uYACGg tetraloop was not found in the cUAUg triloop. However, the triloop uses different structural elements to present a largely similar surface: sequence and underlying architecture are not conserved, but key aspects of the surface structure are. Important structural differences do exist, though, and may account for the observed cross-isotype binding specificities between 3Cpro and SLD.
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Affiliation(s)
- Stephen J Headey
- Institute of Fundamental Sciences, Massey University, Palmerston North, New Zealand
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