Crystal structure of biphalin sulfate: A multireceptor opioid peptide

J. L. Flippen-Anderson, J. R. Deschamps, C. George, V. J. Hruby, A. Misicka, A. W. Lipkowski

Research output: Contribution to journalArticlepeer-review

13 Scopus citations


Biphalin is a dimeric opioid peptide, composed of two tetrapeptides connected 'tail-to-tail', that exhibits a high affinity for all three opioid receptor types (i.e. μ, δ and κ). This study presents the X-ray crystal structure of biphalin sulfate and compares it to other opioids that interact with the same biological targets. Both halves of the molecule have a folded backbone conformation but differ significantly from one another. Residues 1-4 in biphalin, which compare well with the δ selective opioid peptide DADLE, fold into a random coil. Residues 5-8, which can be fit to the μ selective peptide D-TIPP-NH2, exhibit a fairly normal type III′ β bend. Biphalin also exhibits structural similarities with two naltrexone analogs, naltrexonazine and norbinaltorphamine, that are specific to μ and κ receptor sites.

Original languageEnglish (US)
Pages (from-to)123-133
Number of pages11
JournalJournal of Peptide Research
Issue number3
StatePublished - 2002
Externally publishedYes


  • Agonist
  • Analgesic
  • Biphalin
  • Conformation
  • Neuropeptide
  • Opioid receptor ligand
  • X-ray diffraction

ASJC Scopus subject areas

  • Biochemistry
  • Endocrinology


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