S-Layer Glycoproteins and Flagellins: Reporters of Archaeal Posttranslational Modifications

[摘要] Many archaeal proteins undergo posttranslational modifications. S-layer proteins and flagellins have been used successfully to study a variety of these modifications, including N-linked glycosylation, signal peptide removal and lipid modification. Use of these well-characterized reporter proteins in the genetically tractable model organisms,Haloferax volcanii, Methanococcus voltaeandMethanococcus maripaludis,has allowed dissection of the pathways and characterization of many of the enzymes responsible for these modifications. Such studies have identified archaeal-specific variations in signal peptidase activity not found in the other domains of life, as well as the enzymes responsible for assembly and biosynthesis of novel N-linked glycans.In vitro assays for some of these enzymes have already been developed.N-linked glycosylation is not essential for eitherHfx. volcaniior theMethanococcusspecies, an observation that allowed researchers to analyze the role played by glycosylation in the function of both S-layers and flagellins, by generating mutants possessing these reporters with only partial attached glycans or lacking glycan altogether.In future studies, it will be possible to consider questions related to the heterogeneity associated with given modifications, such as differential or modulated glycosylation.

[学科分类] 微生物学和免疫学