The Bruker ultrafleXtreme is a modern MALDI-TOF/TOF instrument with large dynamic and mass ranges. With a typical operating mass resolution of >70,000 (which is what our instrument routinely achieves) and the ability to detect and quantify ions with m/z up to 100,000 (although detection sensitivity drops off significantly after 50,000), the instrument is ideal for imaging of protein distributions in animal and plant tissues. For example, we have measured the distribution of a 38.4 kDa enzyme in turmeric rhizome sections and compared that to the metabolites in the metabolic pathway in which the enzyme functions, leading to confirmation of the role of the protein in that pathway.
We also use the instrument in traditional spotted MALDI protein identification/characterization experiments, where it can be used in top-down proteomic analyses, with direct sequencing of a protein from either the C- or N-terminus possible. In such an application, exact locations of specific post-translational modifications can be determined, as can the ratio of modified versus unmodified residues at specific positions. Importantly, this approach can be used for de novo sequencing of an unknown protein or a protein from a non-model organism.
In an additional application, we we are using the ultrafleXtreme in conjunction with Bruker’s MALDI Biotyper platform to build a database of unusual microorganisms (such as cyanobacteria and actinobacteria), with the goal of expediting the process of isolating new strains.
- TOF/TOF technology provides large dynamic range and very large mass range
- This instrument is able to resolve the singly (predominant) or doubly charged ions that result from MALDI of proteins, thus enabling the measurement of intact proteins in either tissue imaging or spotted MALDI experiments.
- Proteins can be unambiguously identified and quantified.
- High mass resolving power
- We typically run Imaging experiments at mass resolutions of 40,000 to 70,000 FWHM (full width at half maximum).
- Our MALDI-Imaging experiments typically are run with mass accuracy of around 1 ppm error on the ultrafleXtreme.
- MALDI source with Smartbeam II laser
- This fast scanning laser enables MALDI-imaging experiments to be run at significant time savings (and cost) compared to other instruments.
- We typically run experiments at a scan rate of 2 Hz, giving us a mass resolution of over 40,ooo. For higher mass resolution experiments, 1 Hz experiments are sometimes performed.
- The Smartbeam II laser also has a narrow beam, enabling raster spacing of 10 µm without oversampling. This provides for high spatial resolution, just like the 9.4T solariX instrument.
- Optimized ion optics for sensitivity and mass range coverage
- The sensitivity of this instrument exceeds other TOF instruments, and is ideal for tissue imaging experiments of proteins and peptides.