Intact macromolecular assemblies are analysed by advanced mass spectrometry. How large complexes (in molecular weight) have been studied?
['Here we show that the Orbitrap mass analyzer can be used to measure protein assemblies of molecular weights approaching one megadalton with sensitivity down to the detection of single ions.', 'Using this relationship we show that we can determine masses of both 30S subunits and intact 2.3 MDa 70S ribosomes from Thermus thermophilus.', 'We confirm the existence of these subpopulations using tandem mass spectrometry of intact 30S subunits. Overall, the results show that, rather than uniform particles, gas-phase ribosomes consist of a number of discrete populations. More generally, the results establish a rigorous procedure for accurate mass measurement and spectral analysis of heterogeneous macromolecular assemblies.']
['2.3 megadalton']
['2.3 megadalton']