Drastic differences in glycosylation of related S-layer glycoproteins from moderate and extreme halophiles.
The outer surface of the moderate halophilic archaebacterium Haloferax volcanii (formerly named Halobacterium volcanii) is covered with a hexagonally packed surface (S) layer glycoprotein. The polypeptide (794 amino acid residues) contains 7 N-glycosylation sites. Four of these sites were isolated as glycopeptides and the structure of one of the corresponding saccharides was determined. Oligosaccharides consisting of beta-1,4-linked glucose residues are attached to the protein via the linkage unit asparaginyl-glucose. In the related glycoprotein from the extreme halophile Halobacterium halobium, the glucose residues are replaced by sulfated glucuronic acid residues, causing a drastic increase in surface charge density. This is discussed in terms of a recent model explaining the stability of halophilic proteins.
Mengele
R
R
Lehrstuhl Biochemie I, Universität Regensburg, Federal Republic of Germany.
Sumper
M
M
D000595:Amino Acid Sequence; D001425:Bacterial Outer Membrane Proteins / Q000302:isolation & purification / Q000378:metabolism*; D050260:Carbohydrate Metabolism; D002851:Chromatography, High Pressure Liquid; D008401:Gas Chromatography-Mass Spectrometry; D006020:Glycopeptides / Q000302:isolation & purification / Q000378:metabolism*; D006023:Glycoproteins / Q000378:metabolism*; D006031:Glycosylation; D006217:Halobacterium / Q000378:metabolism*; D008969:Molecular Sequence Data; D014357:Trypsin / Q000378:metabolism
D001425:Bacterial Outer Membrane Proteins; D006020:Glycopeptides; D006023:Glycoproteins; D014357:Trypsin