7b4p

Publication Abstract from PubMed

Internalisation of a bacteria by an archaeal cell expedited eukaryotic evolution. An important feature of the species that diversified into the great variety of eukaryotic life visible today was the ability to combat oxidative stress with a copper-zinc superoxide dismutase (CuZnSOD) enzyme activated by a specific, high affinity copper chaperone. Adoption of a single protein interface that facilitates homodimerisation and heterodimerisation was essential, however, its evolution has been difficult to rationalise given the structural differences between bacterial and eukaryotic enzymes. In contrast, no consistent strategy for the maturation of periplasmic bacterial CuZnSODs has emerged. Here, 34 copper-zinc superoxide dismutases are described that closely resemble the eukaryotic form but originate predominantly from aquatic bacteria. Crystal structures of a Bacteroidetes bacterium copper-zinc superoxide dismutase portray both prokaryotic and eukaryotic characteristics and propose a mechanism for self-catalysed disulphide maturation. Unification of a bacterial but eukaryotic-like CuZnSOD along with a ferredoxin-fold MXCXXC copper binding domain within a single polypeptide created the advanced copper delivery system for CuZnSODs exemplified by the human copper chaperone for superoxide dismutase-1. The development of this system facilitated evolution of large and compartmentalised cells following endosymbiotic eukaryogenesis.

Bacterial evolutionary precursors of eukaryotic copper-zinc superoxide dismutases.,Wright GSA Mol Biol Evol. 2021 May 22. pii: 6281076. doi: 10.1093/molbev/msab157. PMID:34021750^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.