Enigmatic Evolutionary History of Porphobilinogen Deaminase in Eukaryotic Phototrophs
Biology Centre CAS, Institute of Parasitology, Branišovská 31, 370 05 České Budějovice, Czech Republic
Faculty of Science, University of South Bohemia, Branišovská 31, 370 05 České Budějovice, Czech Republic
Academic Editor: Andrés Moya
Received: 25 March 2021 / Revised: 21 April 2021 / Accepted: 27 April 2021 / Published: 29 April 2021
The heme pathway is essential for most of cellular life. In eukaryotic phototrophs, the entire pathway is plastid localized. Despite that, the enzyme responsible for the synthesis of hydroxymethylbilane, porphobilinogen deaminase, shows α-proteobacterial instead of expected cyanobacterial origins in rhodophytes, chlorophytes, plants, and most algae with complex plastid. However, no such enzyme has been found in the supposed partners of plastid endosymbioses, the heterotrophic eukaryotes, and cyanobacteria. I propose two scenarios explaining this phenomenon by either endosymbiotic gene transfer from the ancestor of mitochondria or a non-endosymbiotic lateral gene transfer from unspecified α-proteobacterium. Phylogenetic analysis of porphobilinogen deaminases does not reject any of the two proposed evolutionary scenarios.