Origin And Early Evolution Of Alg14/Alg13Dimer Glycosyltransferase

Glycosylation is predominant in post-translational processing. There are many kinds of glycosyltransferases in vivo, forming a supergene family. In eukaryote, Alg14and Alg13are found to be separately expressed but combined together as UDP-GlcNAc transferase in the N-linked glycosylation. They are supposed to be homology to MurG, a widely distributed glycosyltransferase in bacteria. Similarities between N-glycosylation processes in eukaryotes and peptidoglycan synthesis in prokaryotes have also been proposed before, indicating a common evolutionary origin of the two processes. However, the origin and evolution history of the Alg14/Alg13dimer enzyme is not clearly expounded.With exhaustive searches across the public databases and phylogenetic analyses of the two domains, we elucidate the early evolution history and origin pattern of Algl4and Algl3. Here we analyzed three groups of multi-domain protein (containing Alg14and Alg13in a single peptide) in the three kingdoms of life correspondingly. Our results show that Alg14/Alg13in prokaryotes (archaea and bacteria) ought to be original, while the one in eukaryote is secondarily fused. The rare genomic changes and phylogenetic analysis inferred that the dimer enzyme originated from MurG like ancestor, and an unusual gene fission event from a multi-domain protein in bacteria led to the generation of the dimer. Multiple horizontal gene transfer (HGT) events in the early evolution period may be the cause of the scattered distribution of the dimer enzyme in the three kingdoms of life.