Protein fragments identified new types of extremophiles, which survive harsh environments on Earth, and could someday help astrobiologists identify alien life. Credit: Adapted from Journal of Proteome Research 2024, DOI: 10.1021/acs.jproteome.3c00538
Key points:
- Learning more about how microorganisms adapt to hostile environments could provide clues extraterrestrial life.
- The team collected water samples from five high-altitude Andean lakes more than 2.3 miles above sea level in the Chilean Altiplano.
- Instead of traditional DNA sequencing, researchers used protein fragments to identify two new “extremophile” microbes.
Scientists are always intrigued by and researching organisms that live in extreme environments, from deep-sea trenches to mountaintops. Learning more about how microorganisms—called “extremophiles”—adapted to these hostile environments could inform scientists about life on Earth and potential life on other planets.
Typically, researchers use individual gene sequencing to identify microbes based on their DNA. However, current methods can’t distinguish closely related species of extremophiles. So, a team of international researchers turned to the extremophiles’ protein signature as a means of identification.
For the study, published in ACS’ Journal of Proteome Research, the team collected water samples from five high-altitude Andean lakes more than 2.3 miles above sea level in the Chilean Altiplano. From the samples, the researchers cultivated 66 microbes and then determined which of two methods better identified the microorganisms.
Traditional gene sequencing compared the nucleotides of the 16s rRNA from each sample to a database for identification. Meanwhile, the newer “proteotyping” technique analyzed protein fragments—known peptides to produce peptide signatures—which the team used to identify microorganisms from proteome databases. With these methods, the researchers identified 63 of the 66 microorganisms that were cultivated from the high-altitude lake samples. For the three microorganisms that gene sequencing failed to identify because their genetic information wasn’t in the available database, proteotyping identified two potentially new types of extremophile bacteria.
These results suggest proteotyping could be a more complete solution for identifying extremophile microorganisms from small biological samples. The team says protein profiling could someday help the search for and identification of extraterrestrial life, and lead to better exploration of the biodiversity on our own planet.