Related Experiment Video
Updated: Jul 11, 2025

Density Gradient Ultracentrifugation for Investigating Endocytic Recycling in Mammalian Cells
Published on: June 30, 2021
Defining Membrane Protein Localization by Isopycnic Density Gradients
Rhys A Dunstan1,2, Iain D Hay3, Trevor Lithgow4,5
1Centre to Impact AMR, Monash University, Melbourne, VIC, Australia.
Abstract:
Bacterial membrane proteins account for around one-third of the proteome in many species and can represent much more than half of the mass of the membranes. Classic techniques in cell biology can be applied to characterize bacterial membranes and their membrane protein constituents, and here we describe a protocol for the purification of outer membranes and inner membranes from Escherichia coli. This allows for compositional analysis of the membranes as well as functional analyses. The procedure can be applied with minor modifications to other bacterial species including those carrying capsular polysaccharide attached to the outer membrane.
Related Concept Videos
Protein Diffusion in the Membrane
Protein Dynamics in Living Cells
Fluorescent recovery after photobleaching (FRAP) is a fluorescent-protein-based detection technique used to quantify protein movement rates within the cell. This method exposes a small portion of the cell to an intense laser beam. The laser beam causes permanent photobleaching of the fluorophore-tagged proteins in the exposed region. As the bleached...
Subcellular Fractionation
Differential Centrifugation
Differential centrifugation is...
Overview of Protein Sorting and Transport
Protein sorting can be of two types: signal-based sorting and vesicle-based trafficking. In signal-based sorting, specific amino acid sequences called sorting signals target proteins to the proper location inside the cell either via gated transport or by protein translocation. In gated transport, folded...

