Partial molecular characterization of Sm8, a tegumental antigen of Schistosoma mansoni

Abath, Frederico G. C.; Xavier, Edeneide Maria; Montenegro, Sílvia Maria Lucena; Werkhauser, Roberto P.

doi:10.1590/s0074-02762002000900018

Cited by 3 publications

(2 citation statements)

References 12 publications

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“…On the other hand, Smithers et al (22), by using immunoblotting, reported that the principal antigens recognized by antibodies from mice protectively vaccinated with tegumental membranes showed molecular masses of 25, 15, and 13 kDa. The Sm13 tegumental antigen (1) and a calcium binding protein of 8 kDa known as Sm8 (2,20) were specifically recognized in immunoblotting with sera of schistosomiasis patients. On the other hand, a 36-kDa antigen (15) and a highly immunogenic Sm31/32 protein fraction (homologous to S. mansoni cathepsin B and asparaginyl endoprotease, respectively) (25) were found to be useful serologic markers for diagnosing and for differentiating by immunoblotting be- tween acute and chronic schistosomiasis infection in low-transmission areas.…”

Section: Discussionmentioning

confidence: 99%

Detection of Schistosoma mansoni Membrane Antigens by Immunoblot Analysis of Sera of Patients from Low-Transmission Areas

Cesari

Ballén

Mendoza

et al. 2005

Clin Vaccine Immunol

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Schistosoma mansoni surface membrane components play a relevant role in the host-parasite interaction, and some are released in vivo as circulating antigens. n-Butanol extraction favors the release of membrane antigens like alkaline phosphatase, which has been shown to be specifically recognized by antibodies from S. mansoniinfected humans and animals. In the present study, components in the n-butanol extract (BE) of the adult S. mansoni worm membrane fraction were separated by one-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis (1D SDS-PAGE [15%]) and further analyzed by immunoblotting (immunoglobulin G) using defined sera. S. mansoni-infected patient sera, but not sera of uninfected patients or sera obtained from patients infected with other parasite species, specifically and variably recognized up to 20 polypeptides in the molecular mass range of ϳ8 to >80 kDa. There were some differences in the number, intensity, and frequency of recognition of the BE antigens among sera from Venezuelan sites of endemicity with a different status of schistosomiasis transmission. Antigens in the 28-to 24-kDa molecular mass range appeared as immunodominants and were recognized by S. mansoni-positive sera from all the sites, with recognition frequencies varying between 57.5 and 97.5%. Immunoblotting with BE membrane antigens resulted in a highly sensitive (98.1%), specific (96.1.0%), and confirmatory test for the immunodiagnosis of schistosomiasis in low-transmission areas.

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Section: Discussionmentioning

confidence: 99%

Detection of Schistosoma mansoni Membrane Antigens by Immunoblot Analysis of Sera of Patients from Low-Transmission Areas

Cesari

Ballén

Mendoza

et al. 2005

Clin Vaccine Immunol

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“…The other two, FhCaM2 and FhCaM3, are more different at the sequence level (67% and 51% similarity respectively); however they are predicted to have similar overall structures to mammalian calmodulins [12,13]. proteins with one EF-hand and includes FH8 from F. hepatica, Sm8 from S. mansoni and SjCa8 from Schistosoma japonicum [14][15][16]. In the case of FH8, the calcium binding affinity has been shown to be low (K d ~10 -4 M) [16].…”

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FhCaBP3: A Fasciola hepatica calcium binding protein with EF-hand and dynein light chain domains

et al. 2013

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A DNA sequence encoding a protein with predicted EF-hand and dynein light chain binding domains was identified in a Fasciola hepatica EST library. Sequence analysis of the encoded protein revealed that the most similar known protein was the Fasciola gigantica protein FgCaBP3 and so this newly identified protein was named FhCaBP3. Molecular modelling of FhCaBP3 predicted a highly flexible N-terminal region, followed by a domain containing two EF-hand motifs the second of which is likely to be a functioning divalent ion binding site. The C-terminal domain of the protein contains a dynein light chain like region. Interestingly, molecular modelling predicts that calcium ion binding to the N-terminal domain destabilises the β-sheet structure of the C-terminal domain. FhCaBP3 can be expressed in, and purified from, Escherichia coli. The recombinant protein dimerises and the absence of calcium ions appeared to promote dimerisation. Native gel shift assays demonstrated that the protein bound to calcium and manganese ions, but not to magnesium, barium, zinc, strontium, nickel, copper or cadmium ions. FhCaBP3 interacted with the calmodulin antagonists trifluoperazine, N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide and chlorpromazine as well as the myosin regulatory light chain-binding drug praziquantel. Despite sequence and structural similarities to other members of the same protein family from F. hepatica, FhCaBP3 has different biochemical properties to the other well characterised family members, FH22 and FhCaBP4. This suggests that each member of this trematode calcium-binding family has discrete functional roles within the organism.

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FhCaBP4: a Fasciola hepatica calcium-binding protein with EF-hand and dynein light chain domains

et al. 2012

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In trematodes, there is a family of proteins which combine EF-hand-containing domains with dynein light chain (DLC)-like domains. A member of this family from the liver fluke, Fasciola hepatica-FhCaBP4-has been identified and characterised biochemically. FhCaBP4 has an N-terminal domain containing two imperfect EF-hand sequences and a C-terminal dynein light chain-like domain. Molecular modelling predicted that the two domains are joined by a flexible linker. Native gel electrophoresis demonstrated that FhCaBP4 binds to calcium, manganese, barium and strontium ions, but not to magnesium or zinc ions. The hydrophobic, fluorescent probe 8-anilinonaphthalene-1-sulphonate bound more tightly to FhCaBP4 in the presence of calcium ions. This suggests that the protein undergoes a conformational change on ion binding which increases the number of non-polar residues on the surface. FhCaBP4 was protected from limited proteolysis by the calmodulin antagonist W7, but not by trifluoperazine or praziquantel. Protein-protein cross-linking experiments showed that FhCaBP4 underwent calcium ion-dependent dimerisation. Since DLCs are commonly dimeric, it is likely that FhCaBP4 dimerises through this domain. The molecular model reveals that the calcium ion-binding site is located close to a key sequence in the DLC-like domain, suggesting a plausible mechanism for calcium-dependent dimerisation.

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Partial molecular characterization of Sm8, a tegumental antigen of Schistosoma mansoni

Abstract: Sm8 is a major tegumental antigen of

Cited by 3 publications

References 12 publications

Detection of Schistosoma mansoni Membrane Antigens by Immunoblot Analysis of Sera of Patients from Low-Transmission Areas

Detection of Schistosoma mansoni Membrane Antigens by Immunoblot Analysis of Sera of Patients from Low-Transmission Areas

FhCaBP3: A Fasciola hepatica calcium binding protein with EF-hand and dynein light chain domains

FhCaBP4: a Fasciola hepatica calcium-binding protein with EF-hand and dynein light chain domains

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