Detection of Short Peptides as Putative Biosignatures of Psychrophiles via Laser Desorption Mass Spectrometry
peer-reviewed · Astrobiology · 2023
| Date | 2023-06-01 |
| Type | peer-reviewed |
| Venue | Astrobiology |
| Publisher | Mary Ann Liebert |
| Contribution | downstream-application |
| DOI | 10.1089/ast.2022.0138 |
| Citations (OpenAlex) | 2 |
Abstract
Studies of psychrophilic life on Earth provide chemical clues as to how extraterrestrial life could maintain viability in cryogenic environments. If living systems in ocean worlds (e.g., Enceladus) share a similar set of 3-mer and 4-mer peptides to the psychrophile Colwellia psychrerythraea on Earth, spaceflight technologies and analytical methods need to be developed to detect and sequence these putative biosignatures. We demonstrate that laser desorption mass spectrometry, as implemented by the CORALS spaceflight prototype instrument, enables the detection of protonated peptides, their dimers, and metal adducts. The addition of silicon nanoparticles promotes the ionization efficiency, improves mass resolving power and mass accuracies via reduction of metastable decay, and facilitates peptide de novo sequencing. The CORALS instrument, which integrates a pulsed UV laser source and an Orbitrap mass analyzer capable of ultrahigh mass resolving powers and mass accuracies, represents an emerging technology for planetary exploration and a pathfinder for advanced technique development for astrobiological objectives.
Methods and tools
- CORALS peptide biosignature detection: Laser desorption mass spectrometry workflow for detecting and sequencing short peptides as candidate biosignatures on icy ocean worlds such as Enceladus, demonstrated on the CORALS spaceflight prototype: a pulsed UV laser source feeding an Orbitrap mass analyser at ultrahigh mass resolving power and accuracy. Targets the 3-mer and 4-mer peptides found enriched in the psychrophile Colwellia psychrerythraea, on the premise that life persisting in cryogenic extraterrestrial brines might converge on a similar set. Adding silicon nanoparticles raises ionisation efficiency and improves mass resolving power and accuracy by suppressing metastable decay, which is what makes peptide de novo sequencing feasible; protonated peptides, their dimers and metal adducts are all detected. Sequencing rather than database matching is the only option available here, since no reference proteome exists for an unknown organism.