Native Habitats, Native Mass Spectrometry – Extended Mass Range up to m/z 80 000

Exactive Plus EMR mass spectrometer with UltiMate RSLC liquid chromatograph viewed from the right

Growing up, I always had mixed feelings about visiting the zoo. The mere image of animals in cages or behind iron bars would bother me. I did not understand why humans would want to watch captive animals which were removed from their natural habitat on display. Fortunately, I did start to see a trend where zoos began to team up with university research facilities to conduct more research-based studies (e.g. conservation of species). This allowed more animals to be on display in their natural habitats, enabling scientists to observe animal behaviors that may not be apparent in cages. I can only imagine the gain in new insights from observing interactions and behavioral capabilities that are native to these animals.

Quite similarly, native mass spectrometry aims to identify and characterize proteins in their native (intact) state. Thermo Fisher Scientific first introduced the Thermo Scientific™ Exactive™ Plus EMR Obritrap™ LC-MS instrument for native mass spectrometry with targets including monoclonal antibodies, antibody-drug conjugates (ADC), glycoforms, etc. The instrument provides an extended m/z range of 350-20,000, improved transmission of higher-mass ions and high-resolution, accurate-mass capabilities.

At ASMS 2018, look out for the new Thermo Scientific™ Q Exactive ™ UHMR Quadrupole Orbitrap Mass Spectrometer (MS). The Q Exactive UHMR (Ultra-High Mass Range) Quadrupole MS is designed for large intact protein and protein complexes analysis. What are the differences compared to the Exactive Plus EMR Obritrap Mass Spectrometer?

For starters, the Q Exactive UHMR mass spectrometer provides an extended mass range of up to m/z 80,000. Thus, the instrument can enable native mass spectrometry analysis of large protein-nucleic acid assemblies that require very efficient transmission in the ultrahigh mass range as depicted in Figure 1.

The Q Exactive UHMR can release intact membrane protein assemblies in the source region of the mass spectrometer (as opposed to the HCD cell in its predecessor) through a process called ‘in-source trapping.’ This process not only enables desolvation of noncovalent protein complexes, but also reduces their kinetic energy which improves their transmission through the bent flatapole. Lastly, the Q Exactive UHMR’s quadrupole mass filter has ultrahigh precursor selection capability. Hence, the quadrupole can select up to m/z 25,000  ions for selection ion monitoring (SIM) and MS/MS experiments.

Dr. Albert Heck at Utrecht University has used both the Exactive Plus EMR Orbitrap and the Q Exactive UHMR Orbitrap Mass Spectrometer. The Heck lab develops mass spectrometry methods for the structural characterization of proteins but also for better understanding protein complexes and their interactions. Dr. Heck does call out two additional primary benefits of the Q Exactive UHMR Orbitrap Mass Spectrometer below.

“With the introduction, this year of the Q Exactive UHMR, it’s really been a game changer for, I think, mostly two reasons. First, the sensitivity in the mass resolution has increased a lot. We can now record in a matter of seconds or let’s say minutes. So, we use much less sample, and the data looks therefore also better. Another major benefit is that we can do now, MS/MS and pseudo-MS3 on the Q Exactive UHMR, even on these very large protein assemblies, and that’s really a key benefit for identification and analysis of protein assemblies.”

Do check out this NCBI publication by Utrecht University which talks about these benefits in more detail. If you are interested to learn more about the Q Exactive UHMR Orbitrap Mass Spectrometer, stop by the Thermo Fisher Scientific Booth 708 at ASMS this year if you are visiting.

As I mentioned in my most recent blog post, Thermo Fisher Scientific does offer a program where you can trade in your existing LC-MS instrument for an applied discount towards a new Thermo Scientific™ LC-MS system. Additionally, you have the option to purchase factory-certified mass spectrometers which have been fully reconditioned at our centers. These mass spectrometers also come with a one year warranty and are supported by Unity Lab Services (ULS).

Source: analyteguru.com by Monika Verma

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