LitCovid-sample-sentences  

PMC:7253482 / 8961-14443 JSONTXT 25 Projects

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Id Subject Object Predicate Lexical cue
T50 0-46 Sentence denotes Clustering of underprocessed glycans on MERS S
T51 47-196 Sentence denotes We subsequently performed glycopeptide analysis to ascertain the compositions of glycans at all of the potential N-linked glycosylation sites (PNGs).
T52 197-413 Sentence denotes MERS, SARS and HKU1 recombinant S proteins were reduced, alkylated and digested with an assortment of proteases to yield glycopeptides, which were subjected to in-line liquid chromatography-mass spectrometry (LC-MS).
T53 414-522 Sentence denotes This revealed differential levels of oligomannose, hybrid, and complex-type glycan populations (Fig. 2a, b).
T54 523-589 Sentence denotes Using structures of the trimeric MERS and SARS S proteins (PDB ID:
T55 590-746 Sentence denotes 5X59 and 5X58, respectively), we generated models of fully glycosylated coronavirus spikes using experimentally determined glycan compositions (Fig. 3a, b).
T56 747-927 Sentence denotes This revealed that oligomannose-type glycans on MERS S co-localize to specific clusters on the head of the S protein, consisting of glycans at Asn155, Asn166, and Asn236 (Fig. 3a).
T57 928-1114 Sentence denotes We hypothesized that the fully oligomannose-type glycan population in this cluster arises due to the hindered accessibility of glycan processing enzymes to access the substrate glycan28.
T58 1115-1221 Sentence denotes As such, we performed mutagenesis to knock out glycosylation sites with N155A, N166A, and N236A mutations.
T59 1222-1394 Sentence denotes Site-specific analysis of these glycan-KO mutants revealed enhanced trimming of mannose residues, i.e. increased processing, when glycan clustering was reduced (SI Fig. 4).
T60 1395-1556 Sentence denotes The presence of clustered oligomannose-type glycans is reminiscent of that found on other viral glycoproteins, including HIV-1 Env and LASV GPC24,31,34,36,45,46.
T61 1557-1665 Sentence denotes Fig. 2 Quantitative site-specific N-linked glycan analysis of SARS and MERS coronavirus spike glycoproteins.
T62 1666-1810 Sentence denotes Purified (a) MERS and b SARS S proteins were digested. Quantitative site-specific N-linked glycan analysis of a MERS and b SARS S glycoproteins.
T63 1811-1960 Sentence denotes Purified S proteins were digested with trypsin, chymotrypsin, alpha-lytic protease, Glu-C, and trypsin plus chymotrypsin, then analysed by LC-ESI MS.
T64 1961-2081 Sentence denotes Glycan compositions are based on the glycan library generated from negative-ion mass spectrometry of released N-glycans.
T65 2082-2433 Sentence denotes The bar graphs represent the relative quantities of each glycan group with oligomannose-type glycan series (M9 to M5; Man9GlcNAc2 to Man5GlcNAc2) (green), afucosylated and fucosylated hybrid glycans (Hybrid & F Hybrid) (dashed pink), and complex glycans grouped according to the number of antennae and presence of core fucosylation (A1 to FA4) (pink).
T66 2434-2483 Sentence denotes Left to right; least processed to most processed.
T67 2484-2545 Sentence denotes The pie charts summarise the quantification of these glycans.
T68 2546-2668 Sentence denotes Additional compositional information regarding the distribution of fucosylation and sialylation can be found in SI Fig. 3.
T69 2669-2748 Sentence denotes Fig. 3 Structure-based mapping of N-linked glycans on MERS and SARS S proteins.
T70 2749-3008 Sentence denotes The modelling of the experimentally observed glycosylation is illustrated on the prefusion structure of trimeric a MERS S (PDB ID 5X59)11 and b SARS S (PDB ID 5X58)11 glycoproteins. Structural-based mapping of N-linked glycans on a MERS and b SARS S proteins.
T71 3009-3186 Sentence denotes The modelling of the experimentally observed glycosylation is illustrated on the prefusion structure of trimeric MERS S (PDB ID 5X59)11 and SARS S (PDB ID 5X58)11 glycoproteins.
T72 3187-3268 Sentence denotes The glycans are colored according to oligomannose content, as defined by the key.
T73 3269-3390 Sentence denotes DPP4 receptor-binding sites and ACE2 receptor-binding sites for MERS and SARS, respectively, are indicated in light blue.
T74 3391-3465 Sentence denotes The S1 and S2 subunits are colored light grey and dark grey, respectively.
T75 3466-3537 Sentence denotes Fig. 4 Amino-acid sequence diversification across SARS and MERS spikes.
T76 3538-3595 Sentence denotes a Amino-acid diversity in SARS and MERS S gene sequences.
T77 3596-3787 Sentence denotes Averaged values for each domain are also shown below. b Comparison of dN/dS values between buried and exposed residues across SARS and MERS S (n = 70 and 100 for SARS and MERS, respectively).
T78 3788-4046 Sentence denotes The error bars correspond to the 95% highest posterior density intervals while the circles indicate mean dN/dS values. c Mapping of the per residue amino-acid diversity shown in A onto the structures of SARS and MERS S (PDB ID 5X58 and 5X59, respectively)11.
T79 4047-4147 Sentence denotes S proteins are presented as backbone traces with residues colored according to amino-acid diversity.
T80 4148-4254 Sentence denotes Residues with elevated diversity are colored in red, and N-linked glycans are presented as white surfaces.
T81 4255-4445 Sentence denotes Interestingly, SARS and HKU1 (SI Fig. 2) S proteins did not exhibit specific mannose clusters that contribute to the overall mannose abundance, but only isolated glycans were underprocessed.
T82 4446-4624 Sentence denotes We speculate that the oligomannose-type glycans here arise from protein-directed inhibition of glycan processing, as opposed to the glycan-influenced processing observed on MERS.
T83 4625-4837 Sentence denotes Importantly, oligomannose-type glycans has also been implicated in innate immune recognition of coronaviruses by lectins47,48 that recognise these underprocessed glycans as pathogen-associated molecular patterns.
T84 4838-5177 Sentence denotes Given that the receptor-binding domain is the main target of neutralising antibodies8, it is surprising that the DPP4 receptor-binding site of MERS S was not occluded by glycans (Fig. 3a), as observed for other receptor-binding sites of class I viral fusion proteins, including SARS S (Fig. 3b), HIV-1 Env49, LASV GPC24 and influenza HA50.
T85 5178-5482 Sentence denotes We suggest that this is likely due to the intrinsic functionality of the receptor-binding domain of MERS S, that would be sterically hindered by the presence of N-linked glycans, whereas other viruses are able to accommodate the post-translational modifications, without greatly perturbing functionality.