scholarly journals Crystal Structure of Neurotropism-Associated Variable Surface Protein 1 (Vsp1) of Borrelia turicatae

2006 ◽  
Vol 188 (12) ◽  
pp. 4522-4530 ◽  
Author(s):  
Catherine L. Lawson ◽  
Brian H. Yung ◽  
Alan G. Barbour ◽  
Wolfram R. Zückert
Keyword(s):  
Antigenic Variation ◽  
Surface Protein ◽  
Homology Model ◽  
Relapsing Fever ◽  
Disease Manifestation ◽  
Small Water ◽  
Surface Patches ◽  
Variable Surface ◽  
Acidic Glycosaminoglycans ◽  
Selection Of

ABSTRACT Vsp surface lipoproteins are serotype-defining antigens of relapsing fever spirochetes that undergo multiphasic antigenic variation to allow bacterial persistence in spite of an immune response. Two isogenic serotypes of Borrelia turicatae strain Oz1 differ in their Vsp sequences and in disease manifestations in infected mice: Vsp1 is associated with the selection of a neurological niche, while Vsp2 is associated with blood and skin infection. We report here crystal structures of the Vsp1 dimer at 2.7 and 2.2 Å. The structures confirm that relapsing fever Vsp proteins share a common helical fold with OspCs of Lyme disease-causing Borrelia. The fold features an inner stem formed by highly conserved N and C termini and an outer “dome” formed by the variable central residues. Both Vsp1 and OspC structures possess small water-filled cavities, or pockets, that are lined largely by variable residues and are thus highly variable in shape. These features appear to signify tolerance of the Vsp-OspC fold for imperfect packing of residues at its antigenic surface. Structural comparison of Vsp1 with a homology model for Vsp2 suggests that observed differences in disease manifestation may arise in part from distinct differences in electrostatic surface properties; additional predicted positively charged surface patches on Vsp2 compared to Vsp1 may be sufficient to explain the relative propensity of Vsp2 to bind to acidic glycosaminoglycans.

scholarly journals Cryptic and Exposed Invariable Regions of VlsE, the Variable Surface Antigen of Borrelia burgdorferisl

2000 ◽  
Vol 182 (12) ◽  
pp. 3597-3601 ◽  
Author(s):  
Fang Ting Liang ◽  
Jena M. Nowling ◽  
Mario T. Philipp
Keyword(s):  
Lyme Disease ◽  
Borrelia Burgdorferi ◽  
Synthetic Peptides ◽  
Antigenic Variation ◽  
Surface Protein ◽  
Variable Surface ◽  
Antibody Titers ◽  
Negative Surface ◽  
Antipeptide Antibody

ABSTRACT Borrelia burgdorferi, the Lyme disease spirochete, possesses a surface protein, VlsE, which undergoes antigenic variation. VlsE contains two invariable domains and a variable one that includes six variable and six invariable regions (IRs). Five of the IRs are conserved among strains and genospecies of B. burgdorferisensu lato. IR6 is conserved, immunodominant, and exposed at the VlsE surface but not at the spirochete surface, as assessed in vitro. In the present study, the remaining conserved IRs (IR2 to IR5) were investigated. Antisera to synthetic peptides based on each of the IR2 to IR5 sequences were produced in rabbits. Antipeptide antibody titers were similarly high in all antisera. Native VlsE was immunoprecipitable with antibodies to IR2, IR4, and IR5 but not to IR3, indicating that the first three sequences were exposed at the VlsE surface. However, negative surface immunofluorescence and in vitro antibody-mediated killing results indicated that none of the IRs were accessible to antibody at the spirochetal surface in vitro.

scholarly journals Surface Protein Variation by Expression Site Switching in the Relapsing Fever Agent Borrelia hermsii

2000 ◽  
Vol 68 (12) ◽  
pp. 7114-7121 ◽  
Author(s):  
Alan G. Barbour ◽  
Carol J. Carter ◽  
Charles D. Sohaskey
Keyword(s):  
Membrane Protein ◽  
Antigenic Variation ◽  
Surface Protein ◽  
Relapsing Fever ◽  
Borrelia Hermsii ◽  
Immunodeficient Mice ◽  
Major Surface Protein ◽  
Protein Variation ◽  
Expression Site ◽  
Major Surface

ABSTRACT Borrelia hermsii, an agent of relapsing fever, undergoes antigenic variation of serotype-specifying membrane proteins during mammalian infections. When B. hermsii is cultivated in broth medium, one serotype, 33, eventually predominates in the population. Serotype 33 has also been found to be dominant in ticks but not in mammalian hosts. We investigated the biology and genetics of two independently derived clonal populations of serotype 33 of B. hermsii. Both isolates infected immunodeficient mice, but serotype 33 cells were limited in number and were only transiently present in the blood. Probes for vsp33, which encodes the serotype-specifying Vsp33 outer membrane protein, revealed that the gene was located on a 53-kb linear plasmid and that there was only one locus for the gene in serotype 33. The vsp33 probe and probes for other variable membrane protein genes showed that expression of Vsp33 was determined at the level of transcription and that when thevsp33 expression site was active, an expression site for other variable proteins was silent. The study confirmed that serotype 33 is distinct from other serotypes of B. hermsii in its biology and demonstrated that B. hermsii can change its major surface protein through switching between two expression sites.

A Mutation in Paramecium tetraurelia Reveals Functional and Structural Features of Developmentally Excised DNA Elements

Genetics ◽  
1998 ◽  
Vol 148 (1) ◽  
pp. 139-149 ◽  
Author(s):  
Kimberly M Mayer ◽  
Kazuyuki Mikami ◽  
James D Forney
Keyword(s):  
Mutant Cell ◽  
Consensus Sequence ◽  
Surface Protein ◽  
Structural Features ◽  
Inverted Terminal Repeat ◽  
Paramecium Tetraurelia ◽  
Coding Region ◽  
Conserved Sequence ◽  
Variable Surface ◽  
Dna Elements

Abstract The excision of internal eliminated sequences (IESs) from the germline micronuclear DNA occurs during the differentiation of a new macronuclear genome in ciliated protozoa. In Paramecium, IESs are generally short (28–882 bp), AT rich DNA elements that show few conserved sequence features with the exception of an inverted-terminal-repeat consensus sequence that has similarity to the ends of mariner/Tc1 transposons (Klobutcher and Herrick 1995). We have isolated and analyzed a mutant cell line that cannot excise a 370-bp IESs (IES2591) from the coding region of the 51A variable surface protein gene. A single micronuclear C to T transition within the consensus sequence prevents excision. The inability to excise IES2591 has revealed a 28-bp IES inside the larger IES, suggesting that reiterative integration of these elements can occur. Together, the consensus sequence mutation and the evidence for reiterative integration support the theory that Paramecium IESs evolved from transposable elements. Unlike a previously studied Paramecium IES, the presence of this IES in the macronucleus does not completely inhibit excision of its wild-type micronuclear copy through multiple sexual generations.

scholarly journals Targeting the Variable Surface of African Trypanosomes with Variant Surface Glycoprotein-Specific, Serum-Stable RNA Aptamers

2003 ◽  
Vol 2 (1) ◽  
pp. 84-94 ◽  
Author(s):  
Mihaela Lorger ◽  
Markus Engstler ◽  
Matthias Homann ◽  
H. Ulrich Göringer
Keyword(s):  
Antigenic Variation ◽  
Sleeping Sickness ◽  
Rna Aptamers ◽  
Surface Glycoprotein ◽  
Variant Surface Glycoprotein ◽  
Parasite Protein ◽  
African Trypanosomes ◽  
Variable Surface ◽  
New Strategy

ABSTRACT African trypanosomes cause sleeping sickness in humans and Nagana in cattle. The parasites multiply in the blood and escape the immune response of the infected host by antigenic variation. Antigenic variation is characterized by a periodic change of the parasite protein surface, which consists of a variant glycoprotein known as variant surface glycoprotein (VSG). Using a SELEX (systematic evolution of ligands by exponential enrichment) approach, we report the selection of small, serum-stable RNAs, so-called aptamers, that bind to VSGs with subnanomolar affinity. The RNAs are able to recognize different VSG variants and bind to the surface of live trypanosomes. Aptamers tethered to an antigenic side group are capable of directing antibodies to the surface of the parasite in vitro. In this manner, the RNAs might provide a new strategy for a therapeutic intervention to fight sleeping sickness.

scholarly journals Molecular Characterization of Mycoplasma arthritidis Variable Surface Protein MAA2

1998 ◽  
Vol 66 (6) ◽  
pp. 2576-2586 ◽  
Author(s):  
Leigh Rice Washburn ◽  
Keith E. Weaver ◽  
Elizabeth J. Weaver ◽  
Wendy Donelan ◽  
Suhaila Al-Sheboul
Keyword(s):  
Amino Acid ◽  
Signal Peptide ◽  
Dna Sequences ◽  
Surface Protein ◽  
Carboxypeptidase Y ◽  
Coding Region ◽  
Intact Cells ◽  
Mycoplasma Arthritidis ◽  
E Coli ◽  
Variable Surface

Earlier studies implied a role for Mycoplasma arthritidis surface protein MAA2 in cytadherence and virulence and showed that it exhibited both size and phase variability. Here we report the further analysis of MAA2 and the cloning and sequencing of the maa2 gene from two M. arthritidis strains, 158p10p9 and H606, expressing two size variants of MAA2. Triton X-114 partitioning and metabolic labeling with [3H]palmitic acid suggested lipid modification of MAA2. Surface exposure of the C terminus was indicated by cleavage of monoclonal antibody-specific epitopes from intact cells by carboxypeptidase Y. The maa2genes from both strains were highly conserved, consisting largely of six (for 158p10p9) or five (for H606) nearly identical, 264-bp tandem direct repeats. The deduced amino acid sequence predicted a largely hydrophilic, highly basic protein with a 29-amino-acid lipoprotein signal peptide. The maa2 gene was expressed inEscherichia coli from the lacZ promoter of vector pGEM-T. The recombinant product was approximately 3 kDa larger than the native protein, suggesting that the signal peptide was not processed in E. coli. The maa2 gene and upstream DNA sequences were cloned from M. arthritidisclonal variants differing in MAA2 expression state. Expression state correlated with the length of a poly(T) tract just upstream of a putative −10 box. Full-sized recombinant MAA2 was expressed inE. coli from genes derived from both ON and OFF expression variants, indicating that control of expression did not include alterations within the coding region.

MAGNETIC SELECTION OF TRANSDUCED CELLS USING NOVEL SURFACE MARKERS

2021 ◽  
Vol 1 (19) ◽  
pp. 194-196
Author(s):  
O.F Kandarakov ◽  
A.V. Bruter ◽  
A.V. Petrovskaya ◽  
A.V. Belyavsky
Keyword(s):  
Magnetic Separation ◽  
Cell Lines ◽  
Surface Protein ◽  
Cell Selection ◽  
Surface Markers ◽  
Efficiency Of Selection ◽  
Selection Of

The possibility of using HA- and FLAG–tags embedded into CD52 surface protein for magnetic separation of transduced cells in vitro was investigated. The efficiency of selection of transfected cell lines, both with single and binary tags, was shown to exceed 85%. Thus, surface markers on the basis of CD52 protein with integrated HA- and FLAG-tags are applicable for cell selection by the MACS method.

scholarly journals Antigenic Variation of Anaplasma Marginale: Major Surface Protein 2 Diversity during Cyclic Transmission between Ticks and Cattle

2001 ◽  
Vol 69 (5) ◽  
pp. 3057-3066 ◽  
Author(s):  
A. F. Barbet ◽  
Jooyoung Yi ◽  
Anna Lundgren ◽  
B. R. McEwen ◽  
E. F. Blouin ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Salivary Glands ◽  
Antigenic Variation ◽  
Hypervariable Region ◽  
Surface Protein ◽  
Genomic Expression ◽  
Major Surface Protein ◽  
Expression Site ◽  
Major Surface ◽  
Tick Salivary Glands

ABSTRACT The rickettsial pathogen Anaplasma marginale expresses a variable immunodominant outer membrane protein, major surface protein 2 (MSP2), involved in antigenic variation and long-term persistence of the organism in carrier animals. MSP2 contains a central hypervariable region of about 100 amino acids that encodes immunogenic B-cell epitopes that induce variant-specific antibodies during infection. Previously, we have shown that MSP2 is encoded on a polycistronic mRNA transcript in erythrocyte stages of A. marginale and defined the structure of the genomic expression site for this transcript. In this study, we show that the same expression site is utilized in stages of A. marginale infecting tick salivary glands. We also analyzed the variability of this genomic expression site in Oklahoma strain A. marginale transmitted from in vitro cultures to cattle and between cattle and ticks. The structure of the expression site and flanking regions was conserved except for sequence that encoded the MSP2 hypervariable region. At least three different MSP2 variants were encoded in each A. marginalepopulation. The major sequence variants did not change on passage ofA. marginale between culture, acute erythrocyte stage infections, and tick salivary glands but did change during persistent infections of cattle. The variant types found in tick salivary glands most closely resembled those present in bovine blood at the time of acquisition of infection, whether infection was acquired from an acute or from a persistent rickettsemia. These variations in structure of an expression site for a major, immunoprotective outer membrane protein have important implications for vaccine development and for obtaining an improved understanding of the mechanisms of persistence of ehrlichial infections in humans, domestic animals, and reservoir hosts.

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