Glycoconjugate pathway connections revealed by sequence similarity network analysis of the monotopic phosphoglycosyl transferases

Abstract

The monotopic phosphoglycosyl transferase (monoPGT) superfamily comprises over 38,000 nonredundant sequences represented in bacterial and archaeal domains of life. Members of the superfamily catalyze the first membrane-committed step in en bloc oligosaccharide biosynthetic pathways, transferring a phosphosugar from a soluble nucleoside diphosphosugar to a membrane-resident polyprenol phosphate. The singularity of the monoPGT fold and its employment in the pivotal first membrane-committed step allows confident assignment of both protein and corresponding pathway. The diversity of the family is revealed by the generation and analysis of a sequence similarity network for the superfamily, with fusion of monoPGTs with other pathway members being the most frequent and extensive elaboration. Three common fusions were identified: sugar-modifying enzymes, glycosyl transferases, and regulatory domains. Additionally, unexpected fusions of the monoPGT with members of the polytopic PGT superfamily were discovered, implying a possible evolutionary link through the shared polyprenol phosphate substrate. Notably, a phylogenetic reconstruction of the monoPGT superfamily shows a radial burst of functionalization, with a minority of members comprising only the minimal PGT catalytic domain. The commonality and identity of the fusion partners in the monoPGT superfamily is consistent with advantageous colocalization of pathway members at membrane interfaces.

Chemical Biology Tools for Modulating and Visualizing Gram-Negative Bacterial Surface Polysaccharides

“…129,130 In the Gram-negative Aeromonas hydrophila, a related enzyme called WecP instead transfers a GalNAc residue to Und-P to initiate O-antigen biosynthesis. 131 A recent review describes the diverse architectures of another superfamily of bacterial phosphoglycosyl transferases, 132 which will not be discussed here.…”

“…The same reaction is utilized by E. coli WecA to shuttle intermediates into the enterobacterial common antigen (ECA) pathway, which produces a surface polysaccharide that is found in all Enterobacteriaceae family members. , In the Gram-negative Aeromonas hydrophila , a related enzyme called WecP instead transfers a GalNAc residue to Und-P to initiate O-antigen biosynthesis . A recent review describes the diverse architectures of another superfamily of bacterial phosphoglycosyl transferases, which will not be discussed here.…”

Probing Monotopic Phosphoglycosyl Transferases from Complex Cellular Milieu

“…The monoPGT superfamily is exclusively prokaryotic and members share a signature functional core that can be elaborated at the N- or C-terminus with various modalities . A recent sequence similarity network (SSN) analysis has classified over 38,000 nonredundant sequences in the monoPGT superfamily; the SSN has illuminated a wide range of functional domains, including sugar-modifying enzymes, glycosyltransferases, or regulatory domains that may be appended to the monoPGT functional core . The diversification of a common basic scaffold across the superfamily could allow for differential regulation of pathways with shared membrane-embedded substrates.…”

“…11 A recent sequence similarity network (SSN) analysis has classified over 38,000 nonredundant sequences in the monoPGT superfamily; the SSN has illuminated a wide range of functional domains, including sugar-modifying enzymes, glycosyltransferases, or regulatory domains that may be appended to the monoPGT functional core. 12 The diversification of a common basic scaffold across the superfamily could allow for differential regulation of pathways with shared membrane-embedded substrates. In particular, one cluster in the SSN contained PGTs fused to regulatory domains, suggesting that PGTs may play a central role in the regulation of glycoconjugate biosynthesis pathways.…”

Subcellular localization of the enterobacterial common antigen GT‐E‐like glycosyltransferase, WecG

“…followed by a series of three α-helices(O'Toole et al, 2021). The fold was first exhibited and described byKattke et al (2019), where they presented TagA as the first protein to be denoted with the novel fold.…”