PMC:7108637 / 17462-19563 JSONTXT

{"project":"2_test","denotations":[{"id":"29579213-18815311-45167308","span":{"begin":325,"end":329},"obj":"18815311"},{"id":"29579213-20131323-45167309","span":{"begin":346,"end":350},"obj":"20131323"},{"id":"29579213-26088135-45167310","span":{"begin":583,"end":587},"obj":"26088135"},{"id":"29579213-20198110-45167311","span":{"begin":820,"end":824},"obj":"20198110"},{"id":"29579213-20198110-45167312","span":{"begin":950,"end":954},"obj":"20198110"},{"id":"29579213-20131323-45167313","span":{"begin":1290,"end":1294},"obj":"20131323"},{"id":"29579213-27984785-45167314","span":{"begin":1499,"end":1503},"obj":"27984785"},{"id":"29579213-27984785-45167315","span":{"begin":1604,"end":1608},"obj":"27984785"},{"id":"29579213-18815311-45167316","span":{"begin":1798,"end":1802},"obj":"18815311"},{"id":"29579213-19494008-45167317","span":{"begin":1804,"end":1808},"obj":"19494008"},{"id":"T16694","span":{"begin":325,"end":329},"obj":"18815311"},{"id":"T20310","span":{"begin":346,"end":350},"obj":"20131323"},{"id":"T51320","span":{"begin":583,"end":587},"obj":"26088135"},{"id":"T23531","span":{"begin":820,"end":824},"obj":"20198110"},{"id":"T72726","span":{"begin":950,"end":954},"obj":"20198110"},{"id":"T49315","span":{"begin":1290,"end":1294},"obj":"20131323"},{"id":"T90393","span":{"begin":1499,"end":1503},"obj":"27984785"},{"id":"T35878","span":{"begin":1604,"end":1608},"obj":"27984785"},{"id":"T40201","span":{"begin":1798,"end":1802},"obj":"18815311"},{"id":"T1606","span":{"begin":1804,"end":1808},"obj":"19494008"}],"text":"Another concern when analyzing recombinant viral proteins as the source of information for viral glycosylation, is the occasional need for artificial formulations of recombinant viral proteins that often lack natural processing and oligomerization signals when not assembled and presented in the viral context (Bowden et al. 2008; Ritchie et al. 2010). For example, it has been shown that lack of proteolytic cleavage of the membrane-truncated soluble HIV-1 envelope glycoprotein (gp140) resulted in aberrant glycosylation that altered the conformation of the trimer (AlSalmi et al. 2015). Ebola virus glycoprotein represents another example of a highly elaborate protein complex assembly. It exists as three distinct species due to transcriptional stuttering—sGP, GP and ssGP—two of which are secreted (Lee and Saphire 2009). The membrane bound GP is proteolytically processed to GP1 and GP2, and forms a trimer at the cell surface (Lee and Saphire 2009). Nevertheless, formulations of GPs that differ from the natural viral context have been pursued for glycoanalysis. N-glycan analysis was performed for soluble fragment of GP1 and sGP. The GP1 exhibited a mix of complex, hybrid and high-mannose structures, while sGP carried a higher proportion of processed structures (Ritchie et al. 2010). A more recent glycoprofiling of stabilized monomeric GP1,2 constructs from five different strains of Ebola virus confirmed the presence of heterogeneous and mostly complex-type N-glycans (Collar et al. 2016). This is in contrast to a highly variable O-glycan pattern in the different strains (Collar et al. 2016). A few other recombinant glycoproteins from Nipah virus and Machupo virus were expressed in their monomeric forms and reported to predominantly carry complex-type N-glycans (Bowden et al. 2008, 2009). In conclusion, it is difficult to predict glycosylation patterns of native oligomeric protein complexes based on studies of recombinant monomeric proteins. It is, however, sometimes the only solution because of difficulties in expression of correctly folded and authentic protein complexes."}