TY - JOUR

T1 - The Motion of a Single Molecule, the Lambda-Receptor, in the Bacterial Outer Membrane

AU - Oddershede, Lene

AU - Dreyer, Jakob Kisbye

AU - Grego, Sonia

AU - Brown, Stanley

AU - Berg-Sørensen, Kirstine

N1 - 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

PY - 2002

Y1 - 2002

N2 - 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.

AB - 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.

U2 - 10.1016/S0006-3495(02)75318-6

DO - 10.1016/S0006-3495(02)75318-6

M3 - Journal article

C2 - 12496085

VL - 83

SP - 3152

EP - 3161

JO - Biophysical Journal

JF - Biophysical Journal

SN - 0006-3495

IS - 6

ER -