Abstrakt
Venom allergen-like protein (VAL) family is part of the larger sperm coating protein/Tpx-1/Ag5/PR-1/Sc7 (SCP/TAPS) superfamily sharing unique SCP/TAPS protein domain adopting highly conserved α-β-α sandwich conformation. This strong conservation of the tertiary structure and of particular residues within the domain have suggested that all SCP/TAPS domain-containing proteins share a common, yet not elucidated, biological activity.
It has been repeatedly shown that the excretory-secretory products of helminths reflect their diversity in lifestyle and hosts and therefore have little in common between plant and animal parasites. However, members of the VALs superfamily are ubiquitous in these products, and thus it is hypothesized that these proteins are closely associated with the parasitic lifestyle.
Previously, 29 SmVALs with complete SCP/TAPS domains have been identified in the genome of S. mansoni, and these proteins have been extensively studied ever since. With advances in sequencing technologies and methods for processing these data, the quality of the parasite genome has improved significantly in the last decade, but this has not been reflected in VAL protein research.
The originally annotated sequences that are still being respected and worked with are often wrong and the current nomenclature does not reflect the real situation. This consequently amplifies the entropy that prevails in this field, leading to erroneous hypotheses, flawed experimental designs and result misinterpretations.
This work reveals the true spectrum of VAL proteins possessed by S. mansoni and their expression profiles across the life cycle using a meta- study of freely available sequencing data. These data are essential for further investigation of particular molecules and their localization and biological functions in individual parasite stages.