TY - JOUR
T1 - Protein glycosylation in Trypanosoma cruzi. The mechanism of glycosylation and structure of protein-bound oligosaccharides
AU - Parodi, A. J.
AU - Lederkremer, G. Z.
AU - Mendelzon, D. H.
PY - 1983
Y1 - 1983
N2 - As reported previously, label was incorporated first to the glucose residues of protein-bound Glc1Man9GlcNAc2, Glc1Man8GlcNAc2, and Glc1Man7GlcNAc2 when T. cruzi cells, the causative agent of Chagas disease, were incubated with [U-14C] glucose. It is now reported that the glucose residues are removed from the oligosaccharides after a chase period. The relative proportion of Man9GlcNAc2, Man8GlcNAc2, Man7GlcNAc2, and Man6GlcNAc2 appeared to be the same after 120 and 180 min of chase, thus indicating that these compounds were the fully processed protein-bound oligosaccharides. No complex type protein-bound oligosaccharides were detected. Evidence is presented indicating that Glc1Man7GlcNAc2 was formed mainly by glucosylation of Man7GlcNAc2 and not by demannosylation of Glc1Man9GlcNAc2. Man9GlcNAc2 was the first oligosaccharide to be labeled when cells were incubated with [2-3H] mannose. Based on these and previous results, an overall mechanism of protein N-glycosylation is proposed. The structure of the oligosaccharides appeared to be similar to some of those present in human glycoproteins. T. cruzi cells isolated from distant locations in South America were found to share a common mechanism of protein glycosylation.
AB - As reported previously, label was incorporated first to the glucose residues of protein-bound Glc1Man9GlcNAc2, Glc1Man8GlcNAc2, and Glc1Man7GlcNAc2 when T. cruzi cells, the causative agent of Chagas disease, were incubated with [U-14C] glucose. It is now reported that the glucose residues are removed from the oligosaccharides after a chase period. The relative proportion of Man9GlcNAc2, Man8GlcNAc2, Man7GlcNAc2, and Man6GlcNAc2 appeared to be the same after 120 and 180 min of chase, thus indicating that these compounds were the fully processed protein-bound oligosaccharides. No complex type protein-bound oligosaccharides were detected. Evidence is presented indicating that Glc1Man7GlcNAc2 was formed mainly by glucosylation of Man7GlcNAc2 and not by demannosylation of Glc1Man9GlcNAc2. Man9GlcNAc2 was the first oligosaccharide to be labeled when cells were incubated with [2-3H] mannose. Based on these and previous results, an overall mechanism of protein N-glycosylation is proposed. The structure of the oligosaccharides appeared to be similar to some of those present in human glycoproteins. T. cruzi cells isolated from distant locations in South America were found to share a common mechanism of protein glycosylation.
UR - http://www.scopus.com/inward/record.url?scp=0020587404&partnerID=8YFLogxK
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AN - SCOPUS:0020587404
SN - 0021-9258
VL - 258
SP - 5589
EP - 5595
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 9
ER -