Article
Refine
Document Type
- Article (2) (remove)
Language
- English (2) (remove)
Has Fulltext
- yes (2)
Is part of the Bibliography
- no (2)
Keywords
- Biomolecules (2) (remove)
Institute
Publisher
- Elsevier (2)
Ion trajectories have been simulated for an assembly of a linear quadrupole ion-filter and a linear Paul trap with additional pin electrodes for MS SPIDOC, a project in preparation for the study of biomolecules by single-particle imaging with X-ray pulses. The ion-optical components are based on digital RF guiding and trapping fields. In order to carefully handle biomolecules over a wide mass-over-charge range, the module presented consists of separate components for filtering and accumulation/trapping in order to select the ions of interest and to convert the beam from a continuous ion source to ion bunches, respectively, as required for the experiments downstream. The present analysis focuses on the transmission efficiency and mass resolving power of the filter, as well as the buffer-gas-pressure-dependent ion capture and thermalization in the trap for the example of a mass-to-charge ratio equivalent to hemoglobin 15+ ions. The resulting optimized ion bunch delivered by the assembly is characterized.
The spatio-temporal reduction and oxidation of protein thiols is an essential mechanism in signal transduction inall kingdoms of life. Thioredoxin (Trx) family proteins efficiently catalyze thiol-disulfide exchange reactions andthe proteins are widely recognized for their importance in the operation of thiol switches. Trx family proteinshave a broad and at the same time very distinct substrate specificity–a prerequisite for redox switching. Despiteof multiple efforts, the true nature for this specificity is still under debate. Here, we comprehensively compare theclassification/clustering of various redoxins from all domains of life based on their similarity in amino acidsequence, tertiary structure, and their electrostatic properties. We correlate these similarities to the existence ofcommon interaction partners, identified in various previous studies and suggested by proteomic screenings. Theseanalyses confirm that primary and tertiary structure similarity, and thereby all common classification systems, donot correlate to the target specificity of the proteins as thiol-disulfide oxidoreductases. Instead, a number ofexamples clearly demonstrate the importance of electrostatic similarity for their target specificity, independent oftheir belonging to the Trx or glutaredoxin subfamilies