Lamellipodin proline rich peptides associated with native plasma butyrylcholinesterase tetramers

He Li, Lawrence M. Schopfer, Patrick Masson, Oksana Lockridge

Research output: Contribution to journalArticlepeer-review

75 Scopus citations

Abstract

BChE (butyrylcholinesterase) protects the cholinergic nervous system from organophosphorus nerve agents by scavenging these toxins. Recombinant human BChE produced from transgenic goat to treat nerve agent intoxication is currently under development. The therapeutic potential of BChE relies on its ability to stay in the circulation for a prolonged period, which in turn depends on maintaining tetrameric quaternary configuration. Native human plasma BChE consists of 98 % tetramers and has a half-life (t 1/2 ) of 11-14 days. BChE in the neuromuscular junctions and the central nervous system is anchored to membranes through interactions with Co1Q (AChE-associated collagen tail protein) and PRiMA (proline-rich membrane anchor) proteins containing proline-rich domains. BChE prepared in cell culture is primarily monomeric, unless expressed in the presence of proline-rich peptides. We hypothesized that a poly-proline peptide is an intrinsic component of soluble plasma BChE tetramers, just as it is for membrane-bound BChE. We found that a series of proline-rich peptides was released from denatured human and horse plasma BChE. Eight peptides, with masses from 2072 to 2878 Da, were purified by HPLC and sequenced by electrospray ionization tandem MS and Edman degradation. All peptides derived from the same proline-rich core sequence PSPPLPPPPPPPPPPPPPPPPPPPPLP (mass 2663 Da) but varied in length at their N- and C-termini. The source of these peptides was identified through database searching as RAPH1 [Ras-associated and PH domains (pleckstrin homology domains)-containing protein 1; lamellipodin, gi:82581557]. A proline-rich peptide of 17 amino acids derived from lamellipodin drove the assembly of human BChE secreted from CHO (Chinese-hamster ovary) cells into tetramers. We propose that the proline-rich peptides organize the 4 subunits of BChE into a 340 kDa tetramer, by interacting with the C-terminal BChE tetramerization domain.

Original languageEnglish (US)
Pages (from-to)425-432
Number of pages8
JournalBiochemical Journal
Volume411
Issue number2
DOIs
StatePublished - Apr 15 2008

Keywords

  • Acetylcholinesterase (AChE)-associated collagen tail protein (CoiQ)
  • Butyrylcholinesterase (BChE)
  • Lamellipodin
  • Proline-rich attachment domain (PRAD)
  • Proline-rich membrane anchor (PRiMA)
  • Tetramer assembly

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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