Faculty of Biological Sciences

Non-covalent mass analysis

Useful for:

  • Determining complex stoichiometry
  • Detecting multiple protein conformations
  • Characterising oligomerisation behaviour
  • Measuring collisional cross sectional area of complexes with IMS
   
Non-covalent MS

Mass spectrometry can be used to determine sub-unit stoichiometry and heterogeneity of protein complexes by using conditions that can preserve non-covalent interactions into the gas phase.

The success of a non-covalent MS measurment will depend upon the sample purity, concentration and the type of interaction predominating in the complex. Electrostatic interaction tend to be enhanced in the absence of bulk solvent whereas hydrophobic interactions tend to be weakend.

Samples should be buffer exchanged into a volatile ammonium buffer by dialysis or using a spin column. 200 mM ammonium acetate is the recommended buffer but this will vary depending on the required ionic strength and pH. Buffer exchange columns, spin dialysis filters and button dialysis options are avaiable in the Facility if required.

Sample concentration should be greater than 20 uM where possible and a minimal sample volume of 50 uL.

Sample submission

Samples can be submitted to the service at any time by bringing them to the Mass Spec Facility in lab 9.107 of the Astbury building. You should download and complete a sample submission form to bring along with your sample (Please note that results of anlaysis cannot be made available until a grant code has been received). Results for molecular mass analysis are usually available and emailed to you within 48 hous of submission depending on current demand.

Users external to the University can find additional information here.

Notes

The concentrations and volumes stated above are provided as a guide only. We will still accept and attempt MS analysis on samples of lower (or unknown) concentration and/or volume. Where analytes are only stable outside of their preferred buffer for short periods of time, buffer exchange can be performed in the mass spec lab immediatley prior to analysis. Please contact us in advance to arrange this if required.