{"target":"https://pubannotation.org/docs/sourcedb/PMC/sourceid/7199903","sourcedb":"PMC","sourceid":"7199903","source_url":"https://www.ncbi.nlm.nih.gov/pmc/7199903","text":"Highly dense glycan shields, such as those observed on LASV GPC and HIV-1 Env, feature so-called mannose clusters (22, 24) on the protein surface (Fig. 4). Whereas small mannose-type clusters have been characterized on the S1 subunit of Middle East respiratory syndrome (MERS)–CoV S (10), no such phenomenon has been observed for the SARS-CoV-1 or SARS-CoV-2 S proteins. The site-specific glycosylation analysis reported here suggests that the glycan shield of SARS-CoV-2 S is consistent with other coronaviruses and similarly exhibits numerous vulnerabilities throughout the glycan shield (10). Last, we detected trace levels of O-linked glycosylation at Thr323/Ser325 (T323/S325), with over 99% of these sites unmodified (fig. S4), suggesting that O-linked glycosylation of this region is minimal when the structure is native-like.","typesettings":[{"style":"italic","span":{"begin":115,"end":117}},{"style":"italic","span":{"begin":119,"end":121}},{"style":"italic","span":{"begin":284,"end":286}},{"style":"italic","span":{"begin":591,"end":593}},{"style":"superscript","span":{"begin":659,"end":662}},{"style":"superscript","span":{"begin":666,"end":669}}],"project":"LitCovid-sample-PD-HP"}