Postdoctoral Research

Sponsor: Ruth Richardson 
Cornell University
School of Civil and Environmental Engineering

The goals of my postdoctoral work are to develop quantitative tandem mass spectrometry-based proteomic methods to measure bioindicators of the in situ dehalorespiration of perchloroethene (PCE) and trichloroethene (TCE) to ethene. Members of the group Dehalococcoides, who use carbon-chlorine bonds as their sole terminal electron acceptor, are the only known organisms to do this metabolically. This research is possible using the recently sequenced genome of Dehalococcoides ethenogenes Strain 195, a stable, PCE-fed mixed culture of which has been maintained at Cornell for over 10 years.  This research bennefits greatly from our work with the Zinder lab, as well as from the essential resources available at the Proteomics and Mass Spectrometry facility.

   

Quantitative Proteomics

Most of the catalysts for reductive dehalogenation, as well as many of the other oxidoreductases, in the genome of D. ethenogenes are expected to be membrane-bound. Quantitative proteomic analysis of membrane proteins is challenging.  Analysis using iTRAQ labeling techniques allows for multiplex relative quantitation accross up to four samples. Using quantitative in-solution extraction, digestion, iTRAQ tagging, and MDLC/MS/MS, we are attempting to validate a method for the quantitation of differential concentration of all detectable membrane proteins normalized to the total amount of membrane material present using the S-layer protein as an internal standard.

Figure showing quantitative proteomics method