Definition of a saxitoxin (STX) binding code enables discovery and characterization of the anuran saxiphilin family.
Proc Natl Acad Sci U S A
; 119(44): e2210114119, 2022 11.
Article
em En
| MEDLINE
| ID: mdl-36279441
ABSTRACT
American bullfrog (Rana castesbeiana) saxiphilin (RcSxph) 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 (NaVs). How specific RcSxph 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 SxphSTX recognition. The resultant STX "recognition code" enabled engineering of RcSxph to improve its ability to rescue NaVs 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 â¼140 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.
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Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Saxitoxina
/
Neurotoxinas
Limite:
Animals
Idioma:
En
Revista:
Proc Natl Acad Sci U S A
Ano de publicação:
2022
Tipo de documento:
Article