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Molecular basis for the insensitivity of the Monarch ( Danaus plexippus ) to cardiac glycosides
Author(s) -
Holzinger Ferdinand,
Frick Christoph,
Wink Michael
Publication year - 1992
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(92)81530-y
Subject(s) - danaus , manduca sexta , ouabain , monarch butterfly , histidine , asparagine , biology , biochemistry , cardiac glycoside , amino acid , threonine , glycoside , chemistry , lepidoptera genitalia , stereochemistry , insect , serine , botany , phosphorylation , organic chemistry , sodium
The Monarch ( Danaus plexippus ) sequesters cardiac glycosides for its chemical defence against predators. Larvae and adults of this butterfly are insensitive towards dietary cardiac glycosides, whereas other Lepidoptera, such as Manduca sexta and Creatonotos transiens are sensitive and intoxicated by ouabain. Ouiabain inhibits the Na + ,K + ‐ATPase by binding to its α‐subunit. We have amplified and cloned the DNA sequence encoding the respective ouabain binding site. Instead of the amino acid asparagine at position 122 in ouabain‐sensitive insects, the Monarch has a histidine in the putative ouabain binding site, which consists of about 12 amino acids. This change may explain the ouabain insensitivity.