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Comparative biochemical analysis of three members of the Schistosoma mansoni TAL family: Differences in ion and drug binding properties.

Thomas CM, Fitzsimmons CM, Dunne DW, Timson DJ - Biochimie (2014)

Bottom Line: The tegumental allergen-like (TAL) proteins from Schistosoma mansoni are part of a family of calcium binding proteins found only in parasitic flatworms.Despite the presence of two EF-hand-like structures in SmTAL3, neither was predicted to be functional.Overall, these data suggest that the proteins have different biochemical properties and thus, most likely, different in vivo functions.

View Article: PubMed Central - PubMed

Affiliation: School of Biological Sciences, Queen's University Belfast, Medical Biology Centre, 97 Lisburn Road, Belfast, BT9 7BL, UK; Institute for Global Food Security, Queen's University Belfast, 18-30 Malone Road, Belfast, BT9 5BN, UK.

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Dimerisation of the SmTAL proteins. The crosslinking of the SmTAL proteins by BS3 was monitored by 15% SDS-PAGE. M, molecular mass markers (116, 66, 45, 35, 25, 18 kDa); U, Untreated SmTAL protein (SmTAL1 and SmTAL3, 14 μM; SmTAL2, 10 μM); EGTA, reactions carried out in the presence of 0.8 mM EGTA; Ca2+, reactions carried out in 0.8 mM EGTA/1.6 mM calcium chloride; BS3 and associated triangle, increasing concentrations of the crosslinker (50, 150, 500 μM). As a negative control, human galactokinase (HsGALK1, 15 μM) was tested under the same conditions.
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fig4: Dimerisation of the SmTAL proteins. The crosslinking of the SmTAL proteins by BS3 was monitored by 15% SDS-PAGE. M, molecular mass markers (116, 66, 45, 35, 25, 18 kDa); U, Untreated SmTAL protein (SmTAL1 and SmTAL3, 14 μM; SmTAL2, 10 μM); EGTA, reactions carried out in the presence of 0.8 mM EGTA; Ca2+, reactions carried out in 0.8 mM EGTA/1.6 mM calcium chloride; BS3 and associated triangle, increasing concentrations of the crosslinker (50, 150, 500 μM). As a negative control, human galactokinase (HsGALK1, 15 μM) was tested under the same conditions.

Mentions: EF-hand containing proteins (e.g calmodulin, S100 family proteins) and dynein light chains can form homodimers [56,58–61]. Previously, it has been shown that FhCaBP3 forms homodimers, although the extent of dimerization is reduced in the presence of calcium ions [31]. In contrast, FhCaBP4 has a greater tendency to form dimers in the presence of calcium ions [30]. All three SmTAL proteins form dimers in solution as judged by protein–protein crosslinking and SmTAL3 forms higher order oligomers (Fig. 4). Calcium ions did not affect the extent of dimerization by any of the SmTAL proteins (Fig. 4). Control experiments with human galactokinase, which is known to be monomeric from analytical gel filtration experiments [62], showed no crosslinking under the same conditions (Fig. 4). This suggests that, in contrast to FhCaBP3 and FhCaBP4, calcium controlled dimerization does not form part of the mechanism of action of the SmTAL proteins and that all three proteins are likely to function as dimers in vivo.


Comparative biochemical analysis of three members of the Schistosoma mansoni TAL family: Differences in ion and drug binding properties.

Thomas CM, Fitzsimmons CM, Dunne DW, Timson DJ - Biochimie (2014)

Dimerisation of the SmTAL proteins. The crosslinking of the SmTAL proteins by BS3 was monitored by 15% SDS-PAGE. M, molecular mass markers (116, 66, 45, 35, 25, 18 kDa); U, Untreated SmTAL protein (SmTAL1 and SmTAL3, 14 μM; SmTAL2, 10 μM); EGTA, reactions carried out in the presence of 0.8 mM EGTA; Ca2+, reactions carried out in 0.8 mM EGTA/1.6 mM calcium chloride; BS3 and associated triangle, increasing concentrations of the crosslinker (50, 150, 500 μM). As a negative control, human galactokinase (HsGALK1, 15 μM) was tested under the same conditions.
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Related In: Results  -  Collection

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fig4: Dimerisation of the SmTAL proteins. The crosslinking of the SmTAL proteins by BS3 was monitored by 15% SDS-PAGE. M, molecular mass markers (116, 66, 45, 35, 25, 18 kDa); U, Untreated SmTAL protein (SmTAL1 and SmTAL3, 14 μM; SmTAL2, 10 μM); EGTA, reactions carried out in the presence of 0.8 mM EGTA; Ca2+, reactions carried out in 0.8 mM EGTA/1.6 mM calcium chloride; BS3 and associated triangle, increasing concentrations of the crosslinker (50, 150, 500 μM). As a negative control, human galactokinase (HsGALK1, 15 μM) was tested under the same conditions.
Mentions: EF-hand containing proteins (e.g calmodulin, S100 family proteins) and dynein light chains can form homodimers [56,58–61]. Previously, it has been shown that FhCaBP3 forms homodimers, although the extent of dimerization is reduced in the presence of calcium ions [31]. In contrast, FhCaBP4 has a greater tendency to form dimers in the presence of calcium ions [30]. All three SmTAL proteins form dimers in solution as judged by protein–protein crosslinking and SmTAL3 forms higher order oligomers (Fig. 4). Calcium ions did not affect the extent of dimerization by any of the SmTAL proteins (Fig. 4). Control experiments with human galactokinase, which is known to be monomeric from analytical gel filtration experiments [62], showed no crosslinking under the same conditions (Fig. 4). This suggests that, in contrast to FhCaBP3 and FhCaBP4, calcium controlled dimerization does not form part of the mechanism of action of the SmTAL proteins and that all three proteins are likely to function as dimers in vivo.

Bottom Line: The tegumental allergen-like (TAL) proteins from Schistosoma mansoni are part of a family of calcium binding proteins found only in parasitic flatworms.Despite the presence of two EF-hand-like structures in SmTAL3, neither was predicted to be functional.Overall, these data suggest that the proteins have different biochemical properties and thus, most likely, different in vivo functions.

View Article: PubMed Central - PubMed

Affiliation: School of Biological Sciences, Queen's University Belfast, Medical Biology Centre, 97 Lisburn Road, Belfast, BT9 7BL, UK; Institute for Global Food Security, Queen's University Belfast, 18-30 Malone Road, Belfast, BT9 5BN, UK.

Show MeSH