41 research outputs found
An analysis of amino acid sequences surrounding archaeal glycoprotein sequons
No full textDespite having provided the first example of a prokaryal glycoprotein,
little is known of the rules governing the
N-glycosylation process in Archaea. As in Eukarya and
Bacteria, archaeal N-glycosylation takes place at the
Asn residues of Asn-X-Ser/Thr sequons. Since not all sequons are
utilized, it is clear that other factors, including the context in
which a sequon exists, affect glycosylation efficiency. As yet, the
contribution to N-glycosylation made by
sequon-bordering residues and other related factors in Archaea remains
unaddressed. In the following, the surroundings of Asn residues
confirmed by experiment as modified were analyzed in an attempt to
define sequence rules and requirements for archaeal
N-glycosylation
Identification of AglE, a Second Glycosyltransferase Involved in N Glycosylation of the Haloferax volcanii S-Layer Glycoprotein▿
No full textArchaea, like Eukarya and Bacteria, are able to N glycosylate select protein targets. However, in contrast to relatively advanced understanding of the eukaryal N glycosylation process and the information being amassed on the bacterial process, little is known of this posttranslational modification in Archaea. Toward remedying this situation, the present report continues ongoing efforts to identify components involved in the N glycosylation of the Haloferax volcanii S-layer glycoprotein. By combining gene deletion together with mass spectrometry, AglE, originally identified as a homologue of murine Dpm1, was shown to play a role in the addition of the 190-Da sugar subunit of the novel pentasaccharide decorating the S-layer glycoprotein. Topological analysis of an AglE-based chimeric reporter assigns AglE as an integral membrane protein, with its N terminus and putative active site facing the cytoplasm. These finding, therefore, contribute to the developing picture of the N glycosylation pathway in Archaea
