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6O0F

Saxiphilin:STX complex, co-crystal

Summary for 6O0F
Entry DOI10.2210/pdb6o0f/pdb
Related6O0D 6O0E
DescriptorSaxiphilin, [(3aS,4R,10aS)-2,6-diamino-10,10-dihydroxy-3a,4,9,10-tetrahydro-3H,8H-pyrrolo[1,2-c]purin-4-yl]methyl carbamate (3 entities in total)
Functional Keywordssaxitoxin, paralytic shellfish poisoning, antitoxin
Biological sourceLithobates catesbeiana (American bullfrog)
Total number of polymer chains2
Total formula weight189055.18
Authors
Yen, T.J.,Lolicato, M.,Minor, D.L. (deposition date: 2019-02-16, release date: 2019-07-10, Last modification date: 2019-12-04)
Primary citationYen, T.J.,Lolicato, M.,Thomas-Tran, R.,Du Bois, J.,Minor Jr., D.L.
Structure of the saxiphilin:saxitoxin (STX) complex reveals a convergent molecular recognition strategy for paralytic toxins.
Sci Adv, 5:eaax2650-eaax2650, 2019
Cited by
PubMed Abstract: Dinoflagelates and cyanobacteria produce saxitoxin (STX), a lethal bis-guanidinium neurotoxin causing paralytic shellfish poisoning. A number of metazoans have soluble STX-binding proteins that may prevent STX intoxication. However, their STX molecular recognition mechanisms remain unknown. Here, we present structures of saxiphilin (Sxph), a bullfrog high-affinity STX-binding protein, alone and bound to STX. The structures reveal a novel high-affinity STX-binding site built from a "proto-pocket" on a transferrin scaffold that also bears thyroglobulin domain protease inhibitor repeats. Comparison of Sxph and voltage-gated sodium channel STX-binding sites reveals a convergent toxin recognition strategy comprising a largely rigid binding site where acidic side chains and a cation-π interaction engage STX. These studies reveal molecular rules for STX recognition, outline how a toxin-binding site can be built on a naïve scaffold, and open a path to developing protein sensors for environmental STX monitoring and new biologics for STX intoxication mitigation.
PubMed: 31223657
DOI: 10.1126/sciadv.aax2650
PDB entries with the same primary citation
Experimental method
X-RAY DIFFRACTION (2.12 Å)
Structure validation

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