Affinity partitioning of biotinylated mixed liposomes: effect of charge on biotin-NeutrAvidin interaction

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Abstract

The partitioning behaviour of biotinylated mixed liposomes in aqueous poly(ethylene glycol)/dextran two-phase systems containing NeutrAvidin-dextran suggests that the biotin-NeutrAvidin affinity interaction is charge dependent. Biotinylated phosphatidylcholine liposomes with a low negative surface charge distributed in the NeutrAvidin-containing bottom phase at neutral pH, but the introduction of additional negative charges by including phosphatidylserine or the surfactant sodium dodecylsulfate in the liposomes caused them to distribute in the poly(ethylene glycol)-rich top phase instead. By gradually lowering the pH of the affinity two-phase system below the isoelectric point (6.3) of NeutrAvidin, negatively charged phosphatidylserine/phosphatidylcholine liposomes increasingly were attracted by NeutrAvidin to the bottom phase. It is suggested that acidic amino acids present at the rim of the biotin-binding pocket of NeutrAvidin may interact electrostatically with charged residues of the closely apposed liposome surface affecting the affinity interaction.

Detaljer

Författare
  • Irene Barinaga-Rementeria Ramírez
  • Lars Ekblad
  • Bengt Jergil
Enheter & grupper
Forskningsområden

Ämnesklassifikation (UKÄ) – OBLIGATORISK

  • Biologiska vetenskaper

Nyckelord

Originalspråkengelska
Sidor (från-till)389-396
TidskriftJournal of Chromatography. B
Volym743
Utgåva nummer1-2
StatusPublished - 2000
PublikationskategoriForskning
Peer review utfördJa