@misc{10481/81495,
year = {2023},
month = {3},
url = {https://hdl.handle.net/10481/81495},
abstract = {Several mass spectrometry and spectroscopic techniques have been used in the search for molecular biomarkers on Mars. A major constraint is their capability to detect and identify large and complex compounds such as peptides or other biopolymers. Multiplex immunoassays can detect these com-pounds, but antibodies must be produced for a large number of sequence-dependent molecular targets. Ancestral Sequence Re-construction (ASR) followed by protein "resurrection" in the lab can help to narrow the selection of targets. Herein, we propose an immunoanalytical method to identify ancient and universally conserved protein/peptide sequences as targets for identifying ancestral biomarkers in nature. We have developed, tested, and validated this approach by producing antibodies to eight previously described ancestral resurrected proteins (three beta-lactamases, three thioredoxins, one Elongation Factor Tu, and one RuBisCO, all of them theoretically dated as Precambrian), and used them as a proxy to search for any potential feature of them that could be present in current natural environments. By fluorescent sandwich microarray immunoassays (FSMI), we have detected positive immunoreactions with antibodies to the oldest beta-lactamase and thioredoxin proteins (ca. 4 Ga) in samples from a hydrothermal environment. Fine epitope mapping and inhibitory immunoassays allowed the identification of well-conserved epitope peptide sequences that resulted from ASR and were present in the sample. We corroborated these results by metagenomic sequencing and found several genes encoding analogue proteins with significant matches to the peptide epitopes identified with the antibodies. The results demonstrated that peptides inferred from ASR studies have true counterpart analogues in Nature, which validates and strengthens the well-known ASR/protein resurrection technique and our immunoanalytical approach for investigating ancient environments and metabolisms on Earth and elsewhere.},
organization = {Spanish Ministry of Science and Innovation/State Agency of Research RTI2018-094368-B-I00 PID2021-126746NB-I00},
organization = {ERDF A way of making Europe? MCIN/AEI/10.13039/501100011033},
organization = {European Union's Horizon 2020 Research and Innovation Programme under the Marie Sklodowska-Curie Grant
	892961},
organization = {Junta de Andalucia-Consejería de Economía y Conocimiento (PAIDI 2020) P21_00112},
organization = {CAN7 project of the NASA Astrobiology Institute (PAIDI 2020) P21 _00112},
organization = {Instituto de Salud Carlos III  13-13NAI7 _2-0018  PT17/0019},
organization = {European Commission},
publisher = {American Chemical Society},
title = {Immunoanalytical Approach for Detecting and Identifying Ancestral Peptide Biomarkers in Early Earth Analogue Environments},
doi = {10.1021/acs.analchem.2c05386},
author = {Severino, Rita and Risso, Valeria Alejandra and Sánchez Ruiz, José Manuel},
}