Officially debuting at the American Society of Mass Spectrometry conference (Mass Spectrometry and AlliedTopics) in June 2013, the Orbitrap Fusion Tribrid mass spectrometer combines quadrupole, linear ion trap and Orbitrap technologies, offering greater proteome-wide coverage and improved quantitative accuracy. The Fusion Tribrid also can determine relative quantification of proteins in multiple samples simultaneously using tandem mass tags. This instrument makes use of comprehensive mass spectrometry software to analyze data.1
Senko et al. (2013), scientists at Thermo Scientific, recently published a demonstration of the Orbitrap Fusion Tribrid.2 Their demonstration was performed on digested samples of Saccharomyces cerevisiae. In just two hours, the scientists were able to achieve nearly complete coverage of the yeast proteome, known to contain approximately 4,000 proteins; 14,533 mass spectrometry (MS) and 107,413 higher-energy collision dissociation MS/MS spectra were acquired. This corresponds to 29,539 unique peptides (FDR < 1%) and 3,880 proteins—double the amount of proteins identified in comparable experiments with prior Orbitrap hybrid instruments.
The scientists were able to mimic conditions of a 7-Hz MS/MS unpipelined instrument by disabling the pipelining of ion accumulation and spectral acquisition and increasing the maximum injection time from 35 to 80 ms, to compensate for the more efficient isolation and processing speed found in the Fusion Tribrid. By running samples in the not-pipelined and pipelined modes, they found that fully pipelining the instrument collected 2.9x more survey (15,341 versus 5,245) and 2.2x more MS/MS (107,048 versus 49,874) spectra, resulting in 32% more unique peptides and 22% more proteins identified. This also led to an increase in the median protein coverage, from 18.1% to 20.4%.
Interestingly, the ratio of peptide spectral matches to MS/MS acquisitions was higher when instrument operation was not pipelined (53% versus 35%). The authors suggest this is due to species of lower abundance selected when faster instrument settings are used.
Low-abundance species within the soluble proteome were also compared between operating modes.The pipelined samples identified between 25% and 80% more low-abundance proteins; the researchers identified a consistent number of high- and medium-abundance peptides in both modes.
Scientists have made much progress in protein discovery through advancing instrumentation. As this technology continues to expand, we can expect to see substantial improvements in throughput and in the ability to sample low-abundance protein species.
For more details why not visit Thermo Scientific at booth 2441, Pittcon 2014? Full details and registration here http://event1.thermoscientific.com/content/pittcon?ca=pittcon
1. Thermo Fisher Scientific. (2013) “Thermo Fisher Scientific Launches World’s First “Tribrid” LC-MS, Transforming Life Sciences Research with Revolutionary Depth of Analysis and Usability,” press release.
2. Senko, M.W., et al. (2013) “Novel Parallelized Quadrupole/Linear Ion Trap/Orbitrap Tribrid Mass Spectrometer Improving Proteome Coverage and Peptide Identification Rates,” Analytical Chemistry [e-pub ahead of print], doi: 10.1021/ac403115c.
Post Author: Emily Humphreys. As a biology undergraduate at the University of Utah, Emily balanced a heavy class schedule while working long hours in a lab studying eye development. Following graduation, she became involved in infectious disease and aging research involving SNPS.
While she enjoyed the thrill of research, Emily has since traded bench work for science journalism.
And has been a regular contributor to Accelerating Science since 2012.