No lanthanides-based catalysis in eukaryotes

In the "Hypothesis" paper entitled "Lanthanides-Based Catalysis in Eukaryotes" (IUBMB Life 2018 Nov;70(11):1067-1075), we analyzed the possibility that Ce³⁺ -dependent methanol dehydrogenases (MDHs) could be found not only in archaea and bacteria but also in eukaryotic organisms. This hypothesis was based on the observation that MDHs protein sequences carrying the signature of Ce³⁺ -based active sites could be found in genome-derived proteomes of the eukaryotes Plasmodium yoelii yoelii, Nephila clavipes, Hyalella azteca, Pantholops hodgsonii, and Homo sapiens. Data were analyzed following standard procedures employed in the study of phylogenetic relationships among members of protein families and their occurrence in diverse organisms. Furthermore, the study relied on current annotations of protein sequences in the nonredundant protein sequences database, which we did not have any element to doubt about. After the publication of this hypothesis, following analyses carried out by Prof. Huub Op den Camp (Department of Microbiology, Faculty of Science, Radboud University, 6500 GL Nijmegen, The Netherlands), evidence has emerged that the sequences of the putative eukaryotic homologs of bacterial lanthanide-dependent MDHs, identified in our work, either derive from wrong annotation in GenBank or from undetected and pervasive bacterial contamination of the corresponding genomes. Thus, even though our study was technically correct, we were induced to support the initial hypothesis due to annotation errors and undetected bacterial contamination of the relevant genomes in the nucleotide sequences database. Therefore, at present, the hypothesis put forward in our article is not backed up by the currently available data. On a different note, this issue calls for a much higher attention on the integrity/correctness of the data deposited in the sequence databases, a need already highlighted in the literature also for the opposite problem, that is, human contamination of genomic data of other organisms. © 2018 IUBMB Life, 71(3):398-399, 2019.