Journal:Acta Cryst F:S2053230X25003905

Crystal structure of a recombinant mushroom Agaricus bisporus mannose-binding protein with a longer C-terminal region

Dr Hiromi Yoshida ^[1]

Molecular Tour
Agaricus bisporus mannose-binding protein (Abmb, 150 residues) is a ricin B-like type lectin, which has a beta-trefoil fold. Previously reported recombinant C-terminal His-tagged Abmb (additional 12 residues + 6 x His-tag, Abmb168h) showed specific binding activity to mannose and mannitol in surface plasmon resonance analysis. The structure of a recombinant Abmb including additional six residues at the C-terminus after cleavage by TEV protease (Abmb156, PDB code: 5eha) has been reported, however, carbohydrate binding site of Abmb has not yet been determined. The present structure of a recombinant Abmb with a longer C-terminal region (14 residues + 6 x His-tag, Abmb170h, crystalized in two forms, orthorhombic (PDB code: 9udy) and monoclinic (PDB code: 9udz) showed high flexibility of several surface loop regions including C-terminal tail. This recombinant Abmb170h did not show binding affinity toward alpha-D-mannose but showed weak binding affinity toward GalNAc and beta-D-galactose in glycan search assay. The structure of Abmb170h reveals that the C-terminal region has an impact on the sugar binding and would be important to the mannose binding affinity. This can be seen in the comparison of the two Abmb170h structures versus Abmb156.

• Comparing the structures of 9udy vs 5eha we can see plasticity of the C-terminal tail in the .

• Comparing the structures 9udz (in which some loops are not seen) vs 5eha we can see plasticity of the C-terminal tail in the .

• While comparing the structures of 9udy vs 9udz we can see that they look similar in the .

This plasticity in the C-terminal tail region could be related to the carbohydrate binding affinity of Abmb.

References

1. ↑ Yoshida H, Nakakita SI, Rachmawati H, Tjandrawinata RR, Ismaya WT. Crystal structure of a recombinant Agaricus bisporus mushroom mannose-binding protein with a longer C-terminal region. Acta Crystallogr F Struct Biol Commun. 2025 Jun 1. PMID:40349189 doi:10.1107/S2053230X25003905