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Sohi MK, Towne D, Mogallapu R, Chalia A, Ang-Rabanes M. A Case of Olanzapine-Induced Cutaneous Eruption. Am J Case Rep 2023; 24:e941379. [PMID: 37777823 PMCID: PMC10556537 DOI: 10.12659/ajcr.941379] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 08/14/2023] [Accepted: 08/03/2023] [Indexed: 10/02/2023]
Abstract
BACKGROUND Different medication classes have been implicated in cutaneous eruptions that may lead to significant morbidity and mortality. In drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome, the patient may initially present with a cutaneous eruption and hematologic abnormalities which can lead to acute visceral organ involvement if the offending drug is not discontinued. There is also a potential for long-term sequelae such as autoimmune disorders. CASE REPORT A 47-year-old woman with an unknown past medical history and no known drug allergies was admitted to the Behavioral Health Unit, where she was diagnosed with disorganized schizophrenia and started on olanzapine. On day 17 of admission, she developed a diffuse, macular, and erythematous rash on her abdomen, which spread to involve over 50% of her total body surface area. Occipital and posterior auricular lymphadenopathy was present. The patient was treated with prednisone and diphenhydramine. Olanzapine was subsequently discontinued and the patient's rash cleared up. CONCLUSIONS This case report highlights the challenges in diagnosing DRESS syndrome and the potential for antipsychotics to cause DRESS syndrome. DRESS syndrome is a clinical diagnosis augmented by laboratory tests with a wide range of patient presentations. Although there are probability criteria to assist with diagnosis, not all patients will fall exactly into these criteria, which can lead to missed diagnoses and poor patient outcomes. A challenge with DRESS syndrome diagnosis is the latency period between drug initiation and cutaneous eruption. Thus, in differential diagnoses for skin eruptions, temporal associations (minutes, days, weeks) with medications are crucial.
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Affiliation(s)
- Maninder K Sohi
- Eastern Division, West Virginia University School of Medicine, Martinsburg, WV, USA
| | - Devin Towne
- Eastern Region, West Virginia School of Osteopathic Medicine, Martinsburg, WV, USA
| | - Raja Mogallapu
- Department of Behavioral Medicine and Psychiatry, West Virginia University School of Medicine, Martinsburg, WV, USA
| | - Ankit Chalia
- Department of Behavioral Medicine and Psychiatry, West Virginia University School of Medicine, Martinsburg, WV, USA
| | - Michael Ang-Rabanes
- Department of Behavioral Medicine and Psychiatry, West Virginia University School of Medicine, Martinsburg, WV, USA
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Sanderson MR, Laponogov I, Sohi MK, Veselkov DA, Pan XS, Sawhney R, Thompson AW, McAuley K, Fisher LM. Structural insight into the quinolone-DNA cleavage complex of topoisomerase IV from Streptococcus pneumoniae. Acta Crystallogr A 2009. [DOI: 10.1107/s0108767309099206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/03/2023] Open
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Laponogov I, Sohi MK, Veselkov DA, Pan XS, Sawhney R, Thompson AW, McAuley KE, Fisher LM, Sanderson MR. Structural insight into the quinolone-DNA cleavage complex of type IIA topoisomerases. Nat Struct Mol Biol 2009; 16:667-9. [PMID: 19448616 DOI: 10.1038/nsmb.1604] [Citation(s) in RCA: 209] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2009] [Accepted: 04/08/2009] [Indexed: 11/09/2022]
Abstract
Type II topoisomerases alter DNA topology by forming a covalent DNA-cleavage complex that allows DNA transport through a double-stranded DNA break. We present the structures of cleavage complexes formed by the Streptococcus pneumoniae ParC breakage-reunion and ParE TOPRIM domains of topoisomerase IV stabilized by moxifloxacin and clinafloxacin, two antipneumococcal fluoroquinolones. These structures reveal two drug molecules intercalated at the highly bent DNA gate and help explain antibacterial quinolone action and resistance.
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Affiliation(s)
- Ivan Laponogov
- Randall Division of Cell and Molecular Biophysics, King's College London, University of London, London, UK
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4
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Sohi MK, Veselkov DA, Laponogov I, Pan XS, Fisher LM, Sanderson MR. The difficult case of crystallization and structure solution for the ParC55 breakage-reunion domain of topoisomerase IV from Streptococcus pneumoniae. PLoS One 2008; 3:e3201. [PMID: 18787651 PMCID: PMC2527675 DOI: 10.1371/journal.pone.0003201] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2008] [Accepted: 07/08/2008] [Indexed: 11/19/2022] Open
Abstract
Background Streptococcus pneumoniae is the major cause of community-acquired pneumonia and is also associated with bronchitis, meningitis, otitis and sinusitis. The emergence and increasing prevalence of resistance to penicillin and other antibiotics has led to interest in other anti-pneumonococcal drugs such as quinolones that target the enzymes DNA gyrase and topoisomerase IV. During crystallization and in the avenues to finding a method to determine phases for the structure of the ParC55 breakage-reunion domain of topoisomerase IV from Streptococcus pneumoniae, obstacles were faced at each stage of the process. These problems included: majority of the crystals being twinned, either non-diffracting or exhibiting a high mosaic spread. The crystals, which were grown under conditions that favoured diffraction, were difficult to flash-freeze without loosing diffraction. The initial structure solution by molecular replacement failed and the approach proved to be unviable due to the complexity of the problem. In the end the successful structure solution required an in-depth data analysis and a very detailed molecular replacement search. Methodology/Principal Findings Crystal anti-twinning agents have been tested and two different methods of flash freezing have been compared. The fragility of the crystals did not allow the usual method of transferring the crystals into the heavy atom solution. Consequently, it was necessary to co-crystallize in the presence of the heavy atom compound. The multiple isomorphous replacement approach was unsuccessful because the 7 cysteine mutants which were engineered could not be successfully derivatized. Ultimately, molecular replacement was used to solve the structure by sorting through a large number of solutions in space group P1 using CNS. Conclusions/Significance The main objective of this paper is to describe the obstacles which were faced and overcome in order to acquire data sets on such difficult crystals and determine phases for successful structure solution.
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Affiliation(s)
- Maninder K. Sohi
- Randall Division of Cell and Molecular Biophysics, School of Biomedical and Health Sciences, King's College London, London, United Kingdom
| | - Dennis A. Veselkov
- Randall Division of Cell and Molecular Biophysics, School of Biomedical and Health Sciences, King's College London, London, United Kingdom
| | - Ivan Laponogov
- Randall Division of Cell and Molecular Biophysics, School of Biomedical and Health Sciences, King's College London, London, United Kingdom
| | - Xiao-Su Pan
- Molecular Genetics Group, Molecular and Metabolic Signalling Centre, Division of Basic Medical Sciences, St. George's, University of London, London, United Kingdom
| | - L. Mark Fisher
- Molecular Genetics Group, Molecular and Metabolic Signalling Centre, Division of Basic Medical Sciences, St. George's, University of London, London, United Kingdom
- * E-mail: (LMF); (MRS)
| | - Mark R. Sanderson
- Randall Division of Cell and Molecular Biophysics, School of Biomedical and Health Sciences, King's College London, London, United Kingdom
- * E-mail: (LMF); (MRS)
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5
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Laponogov I, Veselkov DA, Sohi MK, Pan XS, Achari A, Yang C, Ferrara JD, Fisher LM, Sanderson MR. Breakage-reunion domain of Streptococcus pneumoniae topoisomerase IV: crystal structure of a gram-positive quinolone target. PLoS One 2007; 2:e301. [PMID: 17375187 PMCID: PMC1810434 DOI: 10.1371/journal.pone.0000301] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2007] [Accepted: 02/21/2007] [Indexed: 11/18/2022] Open
Abstract
The 2.7 A crystal structure of the 55-kDa N-terminal breakage-reunion domain of topoisomerase (topo) IV subunit A (ParC) from Streptococcus pneumoniae, the first for the quinolone targets from a gram-positive bacterium, has been solved and reveals a 'closed' dimer similar in fold to Escherichia coli DNA gyrase subunit A (GyrA), but distinct from the 'open' gate structure of Escherichia coli ParC. Unlike GyrA whose DNA binding groove is largely positively charged, the DNA binding site of ParC exhibits a distinct pattern of alternating positively and negatively charged regions coincident with the predicted positions of the grooves and phosphate backbone of DNA. Based on the ParC structure, a new induced-fit model for sequence-specific recognition of the gate (G) segment by ParC has been proposed. These features may account for the unique DNA recognition and quinolone targeting properties of pneumococcal type II topoisomerases compared to their gram-negative counterparts.
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Affiliation(s)
- Ivan Laponogov
- Randall Division of Cell and Molecular Biophysics, School of Biomedical and Health Sciences, King's College London, London, United Kindgom
| | - Dennis A. Veselkov
- Randall Division of Cell and Molecular Biophysics, School of Biomedical and Health Sciences, King's College London, London, United Kindgom
| | - Maninder K. Sohi
- Randall Division of Cell and Molecular Biophysics, School of Biomedical and Health Sciences, King's College London, London, United Kindgom
| | - Xiao-Su Pan
- Molecular Genetics Group, Molecular and Metabolic Signalling Centre, Division of Basic Medical Sciences, St. George's, University of London, London, United Kindgom
| | - Aniruddha Achari
- Randall Division of Cell and Molecular Biophysics, School of Biomedical and Health Sciences, King's College London, London, United Kindgom
| | - Cheng Yang
- Rigaku Americas Corporation, The Woodlands, Texas, United States of America
| | - Joseph D. Ferrara
- Rigaku Americas Corporation, The Woodlands, Texas, United States of America
| | - L. Mark Fisher
- Molecular Genetics Group, Molecular and Metabolic Signalling Centre, Division of Basic Medical Sciences, St. George's, University of London, London, United Kindgom
| | - Mark R. Sanderson
- Randall Division of Cell and Molecular Biophysics, School of Biomedical and Health Sciences, King's College London, London, United Kindgom
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Affiliation(s)
- B J Sutton
- Biophysics Section, King's College, London, UK
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Wan T, Beavil RL, Fabiane SM, Beavil AJ, Sohi MK, Keown M, Young RJ, Henry AJ, Owens RJ, Gould HJ, Sutton BJ. The crystal structure of IgE Fc reveals an asymmetrically bent conformation. Nat Immunol 2002; 3:681-6. [PMID: 12068291 DOI: 10.1038/ni811] [Citation(s) in RCA: 139] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The distinguishing structural feature of immunoglobulin E (IgE), the antibody responsible for allergic hypersensitivity, is the C epsilon 2 domain pair that replaces the hinge region of IgG. The crystal structure of the IgE Fc (constant fragment) at a 2.6-A resolution has revealed these domains. They display a distinctive, disulfide-linked Ig domain interface and are folded back asymmetrically onto the C epsilon 3 and C epsilon 4 domains, which causes an acute bend in the IgE molecule. The structure implies that a substantial conformational change involving C epsilon 2 must accompany binding to the mast cell receptor Fc epsilon RI. This may be the basis of the exceptionally slow dissociation rate of the IgE-Fc epsilon RI complex and, thus, of the ability of IgE to cause persistent allergic sensitization of mast cells.
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Affiliation(s)
- Tommy Wan
- The Randall Centre, King's College London, New Hunt's House, London SE1 1UL, UK
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8
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Boehm MK, Corper AL, Wan T, Sohi MK, Sutton BJ, Thornton JD, Keep PA, Chester KA, Begent RH, Perkins SJ. Crystal structure of the anti-(carcinoembryonic antigen) single-chain Fv antibody MFE-23 and a model for antigen binding based on intermolecular contacts. Biochem J 2000; 346 Pt 2:519-28. [PMID: 10677374 PMCID: PMC1220881] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Abstract
MFE-23 is the first single-chain Fv antibody molecule to be used in patients and is used to target colorectal cancer through its high affinity for carcinoembryonic antigen (CEA), a cell-surface member of the immunoglobulin superfamily. MFE-23 contains an N-terminal variable heavy-chain domain joined by a (Gly(4)Ser)(3) linker to a variable light-chain (V(L)) domain (kappa chain) with an 11-residue C-terminal Myc-tag. Its crystal structure was determined at 2.4 A resolution by molecular replacement with an R(cryst) of 19.0%. Five of the six antigen-binding loops, L1, L2, L3, H1 and H2, conformed to known canonical structures. The sixth loop, H3, displayed a unique structure, with a beta-hairpin loop and a bifurcated apex characterized by a buried Thr residue. In the crystal lattice, two MFE-23 molecules were associated back-to-back in a manner not seen before. The antigen-binding site displayed a large acidic region located mainly within the H2 loop and a large hydrophobic region within the H3 loop. Even though this structure is unliganded within the crystal, there is an unusually large region of contact between the H1, H2 and H3 loops and the beta-sheet of the V(L) domain of an adjacent molecule (strands DEBA) as a result of intermolecular packing. These interactions exhibited remarkably high surface and electrostatic complementarity. Of seven MFE-23 residues predicted to make contact with antigen, five participated in these lattice contacts, and this model for antigen binding is consistent with previously reported site-specific mutagenesis of MFE-23 and its effect on CEA binding.
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Affiliation(s)
- M K Boehm
- Department of Biochemistry and Molecular Biology, Royal Free Campus, Royal Free and University College Medical School, University College London, Rowland Hill Street, London NW3 2PF, UK
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Farnaud S, Tata R, Sohi MK, Wan T, Brown PR, Sutton BJ. Evidence that cysteine-166 is the active-site nucleophile of Pseudomonas aeruginosa amidase: crystallization and preliminary X-ray diffraction analysis of the enzyme. Biochem J 1999; 340 ( Pt 3):711-4. [PMID: 10359655 PMCID: PMC1220302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
Wild-type and site-specific mutants C166S and C166A (Cys-166-->Ser and Cys-166-->Ala respectively) of the amidase (acylamide amidohydrolase, EC 3.5.1.4) from Pseudomonas aeruginosa were expressed in Escherichia coli by using the vector pKK223-3. Both mutant proteins were catalytically inactive but showed complete cross-reactivity with polyclonal antiserum raised against the wild-type enzyme, as well as CD spectra identical with that of the wild-type enzyme, which were indicative of correct folding. Cys-166 is therefore implicated as the active-site nucleophile. Titration of free thiol groups with 5,5'-dithiobis-(2-nitrobenzoic acid) indicated that Cys-166 is not a rapidly reacting residue. Crystals of both wild-type and C166S amidase grew with identical, rhombohedral morphology; X-ray diffraction analysis established the unit cell dimensions (a=b=c=84 A; alpha=beta=gamma=75 degrees) and space group (R3 or R32). These results imply a quaternary structure of six subunits, with most probably 32 symmetry; the existence of a hexameric structure was supported by molecular mass determinations based on gel filtration and electrophoretic mobility.
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Affiliation(s)
- S Farnaud
- Molecular Biology and Biophysics Section, Division of Biomolecular Sciences, King's College London, Strand, London WC2R 2LS, UK
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10
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Fabiane SM, Sohi MK, Wan T, Payne DJ, Bateson JH, Mitchell T, Sutton BJ. Crystal structure of the zinc-dependent beta-lactamase from Bacillus cereus at 1.9 A resolution: binuclear active site with features of a mononuclear enzyme. Biochemistry 1998; 37:12404-11. [PMID: 9730812 DOI: 10.1021/bi980506i] [Citation(s) in RCA: 185] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The structure of the zinc-dependent beta-lactamase II from Bacillus cereus has been determined at 1.9 A resolution in a crystal form with two molecules in the asymmetric unit and 400 waters (space group P3121; Rcryst = 20.8%). The active site contains two zinc ions: Zn1 is tightly coordinated by His86, His88, and His149, while Zn2 is loosely coordinated by Asp90, Cys168, and His210. A water molecule (W1) lies between the two zinc ions but is significantly closer to Zn1 and at a distance of only 1.9 A is effectively a hydroxide moiety and a potential, preactivated nucleophile. In fact, Asp90 bridges W1 to Zn2, and its location is thus distinct from that of the bridging water molecules in the binuclear zinc peptidases or other binuclear zinc hydrolases. Modeling of penicillin, cephalosporin, and carbapenem binding shows that all are readily accommodated within the shallow active site cleft of the enzyme, and the Zn1-bound hydroxide is ideally located for nucleophilic attack at the beta-lactam carbonyl. This enzyme also functions with only one zinc ion present. The Zn1-Zn2 distances differ in the two independent molecules in the crystal (3.9 and 4.4 A), yet the Zn1-W1 distances are both 1.9 A, arguing against involvement of Zn2 in W1 activation. The role of Zn2 is unclear, but the B. cereus enzyme may be an evolutionary intermediate between the mono- and bizinc metallo-beta-lactamases. The broad specificity of this enzyme, together with the increasing prevalence of zinc-dependent metallo-beta-lactamases, poses a real clinical threat, and this structure provides a basis for understanding its mechanism and designing inhibitors.
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Affiliation(s)
- S M Fabiane
- The Randall Institute, King's College London, U.K
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11
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Abstract
This is the first crystal structure analysis of a complex between an autoantibody and its autoantigen, and it reveals a mode of interaction never before seen in an antibody-antigen complex. Not only are there relatively few antibody contact residues, contributing perhaps to its very low affinity, but these residues are to be found on only one side of the potential combining site surface. Indeed, so many CDR residues are not involved in Fc binding, including those in the central region of the combining site, that it is easy to envisage that this RF may have another, entirely different, specificity. The antibody may therefore have originated in response to another, as yet unidentified, antigen, and the reactivity with IgG Fc may be an unfortunate cross-reactivity. Certainly some of the CDR residues which do interact with IgG Fc are germline encoded, but significantly one of only two residues in the light chain, Pro56, which makes many contacts with Fc, is a somatic mutation. Since this mutation would appear to make a significant contribution to the binding affinity, it is therefore evidence for an antigen driven response to the IgG Fc in the generation of this autoantibody. The Fc epitope recognised by RF-AN is strikingly similar to the binding sites for the bacterial binding proteins A and G, but the significance of this is not clear. What is clear however is that the epitope does not include any part of the Fc carbohydrate residues, although the structure of the complex does reveal that there is an alteration in the carbohydrate conformation when the galactose residues are absent. Loss of the interaction between the terminal galactose residue on the alpha (1-6) linked branch and the C gamma 2 domain appears to allow the carbohydrate chains to become mobile, at the same time exposing a predominantly hydrophobic patch on the C gamma 2 surface. Accessibility to either the agalactosyl carbohydrate chains or the newly exposed residues may account for the enhanced reactivity for G0-IgG that has been reported for certain RFs, and such an epitope need not be very different to that recognised by RF-AN. In order to understand more completely the effect of the presence or absence of the terminal galactose residue, the fully galactosylated glycoform of Fc must be studied for comparison; this work is underway. It is also important now to study a RF which is known to sense this difference in oligosaccharide composition, and also to study RFs of higher affinity, of the IgG class, and from the synovium. RF-AN was the first RF to be immortalised as a cell line, and in many ways it is a typical RF (in terms of specificity, relationship to germline sequence and affinity), but we must now establish whether the novel structural features revealed in this analysis are indeed typical of other RFs. Only when comparisons can be made between RFs of different origin and with contrasting functional properties will we begin to understand what constitutes a pathogenic RF, and the mechanism by which such auto-reactive antibodies are generated.
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Affiliation(s)
- B J Sutton
- Randall Institute, King's College London, UK
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Gardas A, Sohi MK, Sutton BJ, McGregor AM, Banga JP. Purification and crystallisation of the autoantigen thyroid peroxidase from human Graves' thyroid tissue. Biochem Biophys Res Commun 1997; 234:366-70. [PMID: 9177277 DOI: 10.1006/bbrc.1997.6600] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Milligram quantities of the human membrane autoantigen thyroid peroxidase (TPO) have been purified to a high degree of homogeneity by a combination of detergent solubilisation, monoclonal antibody affinity, and ion exchange chromatography, from pooled Graves' disease thyroid glands. The purified TPO of greater than 90% purity was enzymatically active as judged by its ability to oxidise guaiacol. Crystals of TPO have been grown from solutions of the protein solubilised in sodium deoxycholate, in the presence of ammonium sulphate. The crystals exhibited birefringence under polarised light, indicative of molecular order. Crystallisation of this large, membrane autoantigen represents the first step in delineating the complete three-dimensional structure of a human autoantigen involved in destructive thyroiditis.
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Affiliation(s)
- A Gardas
- Medical Centre of Postgraduate Education, Warsaw, Poland
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13
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Corper AL, Sohi MK, Bonagura VR, Steinitz M, Jefferis R, Feinstein A, Beale D, Taussig MJ, Sutton BJ. Structure of human IgM rheumatoid factor Fab bound to its autoantigen IgG Fc reveals a novel topology of antibody-antigen interaction. Nat Struct Biol 1997; 4:374-81. [PMID: 9145108 DOI: 10.1038/nsb0597-374] [Citation(s) in RCA: 183] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Rheumatoid factors are the characteristic autoantibodies of rheumatoid arthritis, which bind to the Fc regions of IgG molecules. Here we report the crystal structure of the Fab fragment of a patient-derived IgM rheumatoid factor (RF-AN) complexed with human IgG4 Fc, at 3.2 A resolution. This is the first structure of an autoantibody-autoantigen complex. The epitope recognised in IgG Fc includes the C gamma 2/C gamma 3 cleft region, and overlaps the binding sites of bacterial Fc-binding proteins. The antibody residues involved in autorecognition are all located at the edge of the conventional combining site surface, leaving much of the latter available, potentially, for recognition of a different antigen. Since an important contact residue is somatic mutation, the structure implicates antigen-driven selection, following somatic mutation of germline genes, in the production of pathogenic rheumatoid factors.
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Affiliation(s)
- A L Corper
- Randall Institute, King's College London, UK
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Sohi MK, Corper AL, Wan T, Steinitz M, Jefferis R, Beale D, He M, Feinstein A, Sutton BJ, Taussig MJ. Crystallization of a complex between the Fab fragment of a human immunoglobulin M (IgM) rheumatoid factor (RF-AN) and the Fc fragment of human IgG4. Immunol Suppl 1996; 88:636-41. [PMID: 8881769 PMCID: PMC1456622 DOI: 10.1046/j.1365-2567.1996.d01-692.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Rheumatoid factors (RF) are the characteristic autoantibodies found in patients with rheumatoid arthritis. They recognize epitopes in the Fc region of immunoglobulin G (IgG) and are often of the IgM isotype. In order to analyse the nature of RF-Fc interactions, we have crystallized a complex between the Fab fragment of a human monoclonal IgM rheumatoid factor (RF-AN) and the Fc fragment of human IgG4. The stoichiometry of the complex within the crystals was found to be 2:1 Fab:Fc. The crystals diffracted X-rays to 0.3 nm resolution, and the space group was C2, with cell dimensions a = 16.03 nm, b = 8.19 nm, c = 6.42 nm, beta = 98.3 degrees. We have also determined the sequence of the variable region of the RF-AN light chain, not hitherto reported. This belongs to the V lambda III-a subgroup and is closely related to the germline gene Humlv318, from which it differs in three amino acid residues. This is the first reported crystallized complex between a human autoantibody and its autoantigen.
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Affiliation(s)
- M K Sohi
- Randall Institute, King's College London, UK
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Sohi MK, Wan T, Sutton BJ, Atkinson T, Atkinson MA, Murphy JP, Bottomley SP, Gore MG. Crystallization and X-ray analysis of a single fab binding domain from protein L of Peptostreptococcus magnus. Proteins 1995; 23:610-2. [PMID: 8749861 DOI: 10.1002/prot.340230420] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Protein L is a multidomain cell wall constituent of certain strains of Peptostreptococcus magnus which binds to the variable domain of immunoglobulin kappa-light chains. A single immunoglobulin-binding domain of M(r) = 9000 from this protein has been isolated and crystallized. The crystals are of space group P4(2)2(1)2, with cell dimensions a = b = 66.9 A, c = 68.3 A, and diffract to at least 2.2 A resolution. The asymmetric unit of the crystal contains two molecules of the protein L domain, related by a noncrystallographic 2-fold axis, as revealed by a self-rotation function calculated with native diffraction data.
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Affiliation(s)
- M K Sohi
- Biomedical Sciences Division, King's College London, UK
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Sohi MK, Sutton BJ, Corper AL, Wan T, Maini RN, Brown C, Rijnders T, Beale D, Feinstein A, Humphreys AS. Crystallization and preliminary X-ray analysis of the Fab fragment of a human monoclonal IgM rheumatoid factor (2A2). J Mol Biol 1994; 242:706-8. [PMID: 7932727 DOI: 10.1006/jmbi.1994.1620] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Crystals of the Fab fragment of a human monoclonal IgM rheumatoid factor have been obtained and are suitable for X-ray structure determination. This molecule, derived from the synovial B cells of a patient with rheumatoid arthritis, is an autoantibody with specificity for IgG Fc. The crystals have space group P2(1), cell dimensions a = 69.0 A, b = 76.6 A, c = 98.8 A and beta = 90.6 degrees, and diffract to a resolution of at least 2.8 A.
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Affiliation(s)
- M K Sohi
- Randall Institute, King's College London, U.K
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Bonanou-Tzedaki SA, Sohi MK, Arnstein HR. The role of cAMP and calcium in the stimulation of proliferation of immature erythroblasts by erythropoietin. Exp Cell Res 1987; 170:276-89. [PMID: 3036549 DOI: 10.1016/0014-4827(87)90306-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The hypothesis that cAMP or calcium are the second messengers of erythropoietin (Epo) was tested on fractionated, Epo-responsive immature erythroblasts from anemic rabbit bone marrow by examining whether the proliferative effects of the hormone could be mimicked by agents that increase the intracellular concentration of cAMP or Ca2+. None of the compounds tested (including 10(-6)-10(-4) M db-cAMP, forskolin, isoprenaline or 10(-7)-10(-6) M of the calcium ionophore A23187) alone or in combination could either initiate or potentiate the mitogenic action of the hormone. Furthermore, addition of 0.2 U/ml erythropoietin produced no permanent or transient increase in the uptake of 45Ca2+ by erythroblasts at 37 degrees C. However, cells cultured with imidazole or cordycepin (which reduce the level of intracellular cAMP), or with the calcium chelator EGTA, or the drugs verapamil or TMB-8 (which interfere with the utilization of extracellular or intracellular calcium) showed a decreased stimulation of DNA synthesis by Epo. Finally, the tumour promoter phorbol ester TPA could partially mimic the action of Epo when added to cultures containing more immature progenitor cells. We conclude then that an artificial increase in the cytoplasmic concentration of either cAMP or Ca2+ is not sufficient to elicit the proliferation of Epo-responsive cells.
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Westermann P, Sohi MK, Arnstein HR. The 66 kDa component of eukaryotic initiation factor 3 interacts with globin mRNA and 18 S rRNA in preinitiation complexes. FEBS Lett 1986; 205:171-4. [PMID: 3743772 DOI: 10.1016/0014-5793(86)80891-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The 66 kDa protein present in a complex with globin mRNA and 18 S rRNA [(1984) Eur. J. Biochem. 143, 27-33] has been reincorporated into functional eukaryotic initiation factor 3 (eIF-3) under conditions of protein synthesis. Additionally, two-dimensional polyacrylamide gel electrophoresis has been used to demonstrate the identity of the 66 kDa protein with the 66 kDa subunit of eIF-3.
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Bonanou-Tzedaki SA, Sohi MK, Arnstein HR. The effect of haemin on RNA synthesis and stability in differentiating rabbit erythroblasts. Eur J Biochem 1984; 144:589-96. [PMID: 6208026 DOI: 10.1111/j.1432-1033.1984.tb08506.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Haemin accelerates the maturation of erythroid cells but whether this is the result of increased globin gene transcription or processing and stabilization of globin mRNA is not clear. The effect of haemin on the synthesis and stability of non-globin messengers is also unknown. We examined the changes that occur in RNA metabolism when anaemic rabbit bone marrow erythroblasts, fractionated into immature and mature fractions, are cultured with 20 microM or 50 microM haemin for brief periods (5-8 h). With both cell types haemin increases the incorporation of [3H]uridine into newly synthesized RNA, particularly into the poly(A)-rich fraction which can increase threefold. Haemin also increases the synthesis of globin mRNA (up to 500% absolutely and 50% relative to the synthesis of total RNA) in the immature, but not in the mature, cells. These results suggest that haemin increases the transcription of both globin and non-globin mRNAs and that the relative increase of each depends on the stage of erythroid cell development. When the [3H]RNA from prelabelled cells was chased in the presence of haemin (with or without actinomycin D) the proportion of 3H remaining in globin mRNA increased in the immature, but not in the mature, cells. These changes in the relative concentration of globin mRNA were also shown by the translation of extracted bone marrow RNAs in a nuclease-treated reticulocyte lysate. We conclude that a secondary effect of haemin is on RNA stability and that it enhances the accumulation of globin mRNA by both molecular and cellular mechanisms.
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