New Method to Study Microbial “First Responder” Proteins


Proteins found in the surface membranes of cells are essential for maintaining normal biological functions in cells, and often are the “first responders” to environmental stimuli. But membrane proteins can be low in abundance and insoluble, making them challenging to quantify and purify. To meet this challenge, scientists at Pacific Northwest National Laboratory developed a strategy to quantify and purify proteins on the surface membranes of cells. Using capabilities at the Environmental Molecular Sciences Laboratory (EMSL), a team of scientists enriched surface membrane proteins expressed by the bacterium Shewanella oneidensis MR-1, using a membrane-impermeable chemical probe. By linking this method with post-digestion stable isotope labeling, surface proteins could be quantified. Armed with this technique, scientists can better study the function of many bacterial membrane proteins.


Zhang H, RN Brown, W-J Qian, ME Monroe, SO Purvine, RJ Moore, MA Gritsenko, L Shi, MF Romine, JK Fredrickson, L Paaa-Tolic, RD Smith, and MS Lipton. 2010. “Quantitative Analysis of Cell Surface Membrane Proteins using Membrane-Impermeable Chemical Probe Coupled with 18O Labeling.” Journal of Proteome Research 9:2160-2169.