Hookworm SCP/TAPS protein structure--A key to understanding host-parasite interactions and developing new...

Area of Science:

• Parasitology
• Structural Biology
• Biochemistry

Background:

• SCP/TAPS proteins are abundant in parasite secretomes, but their functions in nematodes like hookworms are poorly understood.
• Ancylostoma-secreted proteins (ASPs) from the canine hookworm, Ancylostoma caninum, are categorized into at least three groups.
• Comparative modeling suggests ASPs possess an equatorial groove for binding peptides or glycans.

Purpose of the Study:

• To elucidate the structure-function relationships of Ancylostoma-secreted proteins (ASPs).
• To determine the three-dimensional crystal structure of Ac-ASP-7, an ASP highly expressed during the parasitic transition of A. caninum.
• To identify potential functional sites and interactions of Ac-ASP-7.

Main Methods:

• X-ray crystallography was used to determine the 3D structure of Ac-ASP-7.
• Anomalous diffraction was employed to identify metal binding sites.
• Comparative modeling and crystal-packing analysis were utilized to understand protein structure and potential dimerization.

Main Results:

• The crystal structure of Ac-ASP-7 revealed a topology consistent with pathogenesis-related proteins and a C-terminal extension resembling the Hinge domain.
• A novel metal binding site was identified in the C-terminal extension of Ac-ASP-7 via anomalous diffraction.
• Ac-ASP-7 exists in a monomer-dimer equilibrium, with crystal packing suggesting a homo-dimer interface containing a novel divalent metal ion binding site.

Conclusions:

• The identified metal binding site in the Ac-ASP-7 dimer interface may mediate parasite-host interactions at a molecular level.
• Understanding the structure and function of ASPs like Ac-ASP-7 is crucial for parasitic disease control.
• Structural and functional insights into ASPs offer potential for biotechnological applications in combating parasitic diseases.