Protein Analysis and Proteomics

Overview

The Protein Analysis and Proteomics Group (PA&P) is based at the London Research Institute's Clare Hall Laboratories  and provides dedicated proteomic technologies support.

Through the development of advanced methods and the implementation of state of the art mass spectrometers, the PA&P laboratory aims to assist research scientists at the Institute solve difficult or previously intractable problems in biomedical research. Methods for protein and peptide isolation, separations, quantification, identification and characterisation together with expert guidance in study design, are integrated into expertise offered by the group.

Electrospray ionization mass spectrometry is the fundamental technology employed by PA&P for both qualitative and quantitative characterisation of proteins. The principal approach for protein analysis is 'bottom-up' proteomics, where proteins are initially enzymatically digested with proteases producing a peptide pool representative of the original proteins.

Qualitative protein identifications, together with the identification of sites and nature of post-translational modifications are performed using nano-scale capillary LC gradient separations coupled to either a hybrid Q-ToF mass spectrometer (Waters SYNAPT HDMS) or linear ion trap mass spectrometer (ThermoFisher LTQ XL/ETD). The LC separation allows for the analysis of more complex samples and a more confident identification of larger numbers of peptides.

The PA&P laboratory utilises two techniques for mass spectrometric based relative protein quantification. Differential protein expression can be performed using either an isotope labelling technology for parallel processing of up to 8 samples within a single experiment (Applied Biosystems iTRAQ reagents), or a Stable Isotope Labelling by Amino acids in cell Culture (SILAC) approach, which relies on metabolic incorporation of the quantitative label.

In order for the group to ensure that the Institute continues to have access to the most current proteomic techniques, members of the PA&P laboratory regularly attend national and international meetings on mass spectrometry and proteomics.