8D6Q

Rana catesbeiana saxiphilin mutant - Y558I

Summary for 8D6Q

• Entry DOI: 10.2210/pdb8d6q/pdb
• Descriptor: Saxiphilin (2 entities in total)
• Functional Keywords: saxiphilin, toxin resistance, saxitoxin, antitoxin
• Biological source: Lithobates catesbeianus (American bullfrog)
• Total number of polymer chains: 2
• Total formula weight: 187805.98

Authors

Chen, Z.,Zakrzewska, S.,Minor, D.L. (deposition date: 2022-06-06, release date: 2022-11-02, Last modification date: 2024-11-06)

Primary citation

Chen, Z.,Zakrzewska, S.,Hajare, H.S.,Alvarez-Buylla, A.,Abderemane-Ali, F.,Bogan, M.,Ramirez, D.,O'Connell, L.A.,Du Bois, J.,Minor Jr., D.L.
Definition of a saxitoxin (STX) binding code enables discovery and characterization of the anuran saxiphilin family.
Proc.Natl.Acad.Sci.USA, 119:e2210114119-e2210114119, 2022

PubMed Abstract: American bullfrog () saxiphilin (Sxph) is a high-affinity "toxin sponge" protein thought to prevent intoxication by saxitoxin (STX), a lethal bis-guanidinium neurotoxin that causes paralytic shellfish poisoning (PSP) by blocking voltage-gated sodium channels (Nas). How specific Sxph interactions contribute to STX binding has not been defined and whether other organisms have similar proteins is unclear. Here, we use mutagenesis, ligand binding, and structural studies to define the energetic basis of Sxph:STX recognition. The resultant STX "recognition code" enabled engineering of Sxph to improve its ability to rescue Nas from STX and facilitated discovery of 10 new frog and toad Sxphs. Definition of the STX binding code and Sxph family expansion among diverse anurans separated by ∼140 My of evolution provides a molecular basis for understanding the roles of toxin sponge proteins in toxin resistance and for developing novel proteins to sense or neutralize STX and related PSP toxins.

PubMed: 36279441
DOI: 10.1073/pnas.2210114119

Experimental method

X-RAY DIFFRACTION (2.7 Å)