Dynamics of Macromolecular Assemblies by Mass Spectrometry: From Domain Motions to Virus Maturation

Monday, 27 July, 2015 - 12:00 to 13:00

Presented by Associate Professor Ganesh Anand, National University of Singapore

The inherent dynamic ability of proteins to exist in ensembles of multiple conformations not unlike “molecular springs” in solution, is a prerequisite for function. An understanding of protein dynamics is therefore key for correlation of form (structure) with function.  Our research has been pioneering applications of structural mass spectrometry, consisting of amide hydrogen/deuterium exchange mass spectrometry (HDXMS) and ion mobility mass spectrometry for studying the effects on dynamics of various perturbations on target proteins including signaling proteins, membrane receptors and viruses (large macromolecular assemblies).

The first part of the talk will describe applications of mass spectrometry to mapping interactions in transient protein complexes and a description of allostery in second messenger cyclic adenosine monophosphate (cAMP) signaling. The second part of the talk will talk about the effects of physical perturbations in the form of osmolality on membrane receptors (osmosensing in bacteria). The final part will focus on bacteriophage dynamics and whole proteome dynamics of the Dengue virus particle at two temperatures, 28 ºC ( the temperature in the mosquito vector) and 37 ºC ( the temperature in the human host).

These results have enabled localization of viral breathing and modeling of the structural rearrangements in the viral coat. Our results offer insights into the role of the lipid bilayer in mediating temperature-dependent expansion and maturation of Dengue virus and have major implications for identification of cryptic linear epitopes for targeted antibody discovery.