Posttranslational Protein Modification inArchaea

Abstract

One of the first hurdles to be negotiated in the postgenomic era involves the description of the entire protein content of the cell, the proteome. Such efforts are presently complicated by the various posttranslational modifications that proteins can experience, including glycosylation, lipid attachment, phosphorylation, methylation, disulfide bond formation, and proteolytic cleavage. Whereas these and other posttranslational protein modifications have been well characterized in Eucarya and Bacteria, posttranslational modification in Archaea has received far less attention. Although archaeal proteins can undergo posttranslational modifications reminiscent of what their eucaryal and bacterial counterparts experience, examination of archaeal posttranslational modification often reveals aspects not previously observed in the other two domains of life. In some cases, posttranslational modification allows a protein to survive the extreme conditions often encountered by Archaea. The various posttranslational modifications experienced by archaeal proteins, the molecular steps leading to these modifications, and the role played by posttranslational modification in Archaea form the focus of this review

Identification of AglE, a Second Glycosyltransferase Involved in N Glycosylation of the Haloferax volcanii S-Layer Glycoprotein

“…Since then, various proteins experiencing this posttranslational modification, as well as lipid-linked oligosaccharide intermediates apparently involved in the pathway, have been described in Archaea (9,16,22). Recently, various groups have begun deciphering the archaeal N-glycosylation process in a variety of organisms, such as Methanococcus voltae, Pyrococcus furiosus, and H. volcanii (1,2,7,14).…”

“…Despite the fact that numerous examples of N-glycosylated proteins have been reported in Archaea (9,22,27,28), including the surface (S)-layer glycoprotein of the haloarchaeon Halobacterium salinarum, the first noneukaryal glycoprotein to be described in detail (17,23), little is known of the enzymatic steps involved in the archaeal version of this posttranslational modification. Recently, however, the first systematic examinations of the archaeal N glycosylation pathway have been undertaken.…”

Haloferax volcanii AglB and AglD are Involved in N-glycosylation of the S-layer Glycoprotein and Proper Assembly of the Surface Layer

“…[1][2][3][4] The process is best understood in Eukarya, where N-glycosylation begins with assembly of a dolichol pyrophosphate-linked oligosaccharide on the cytoplasmic face of the endoplasmic reticulum (ER). 1,[4][5][6][7] This lipid-linked oligosaccharide is then reoriented to face the ER lumen, where additional sugar subunits are added.…”

Mechanisms of Evolutionary Innovation Point to Genetic Control Logic as the Key Difference Between Prokaryotes and Eukaryotes

“…DNA base modification is achieved in bacteria, archaea and eukaryotes by unrelated systems (Cao et al 2003;Chan et al 2004;Gaspin et al 2000;Kumar et al 1994). Modification of proteins to alter their interactions with DNA by protein methylation (Baumann et al 1994;Eichler and Adams 2005;Martin and Zhang 2005;Reisenauer et al 1999 …”