The Motion of a Single Molecule, the Lambda-Receptor, in the Bacterial Outer Membrane

Research output: Contribution to journalJournal articleResearchpeer-review

  • Lene Oddershede
  • Jakob Kisbye Dreyer
  • Sonia Grego
  • Brown, Stanley
  • Kirstine Berg-Sørensen
Using optical tweezers and single particle tracking, we have revealed the motion of a single protein, the lambda-receptor, in the outer membrane of living Escherichia coli bacteria. We genetically modified the lambda-receptor placing a biotin on an extracellular site of the receptor in vivo. The efficiency of this in vivo biotinylation is very low, thus enabling the attachment of a streptavidin-coated bead binding specifically to a single biotinylated lambda-receptor. The bead was used as a handle for the optical tweezers and as a marker for the single particle tracking routine. We propose a model that allows extraction of the motion of the protein from measurements of the mobility of the bead-molecule complex; these results are equally applicable to analyze bead-protein complexes in other membrane systems. Within a domain of radius approximately 25 nm, the receptor diffuses with a diffusion constant of (1.5 +/- 1.0) x 10(-9) cm(2)/s and sits in a harmonic potential as if it were tethered by an elastic spring of spring constant of ~1.0 x 10(-2) pN/nm to the bacterial membrane. The purpose of the protein motion might be to facilitate transport of maltodextrins through the outer bacterial membrane.
Original languageEnglish
JournalBiophysical Journal
Issue number6
Pages (from-to)3152-61
Number of pages9
Publication statusPublished - 2002

Bibliographical note

Keywords: Bacterial Outer Membrane Proteins; Biotin; Biotinylation; Computer Simulation; Elasticity; Escherichia coli; Lasers; Micromanipulation; Microspheres; Models, Biological; Models, Chemical; Motion; Nanotechnology; Optics and Photonics; Particle Size; Porins; Protein Conformation; Receptors, Virus; Recombinant Proteins; Streptavidin; Stress, Mechanical

ID: 128538