PMC:7795856 / 9142-10291 JSONTXT

{"project":"LitCovid-PubTator","denotations":[{"id":"209","span":{"begin":404,"end":407},"obj":"Gene"},{"id":"210","span":{"begin":416,"end":419},"obj":"Gene"},{"id":"211","span":{"begin":658,"end":661},"obj":"Gene"},{"id":"212","span":{"begin":484,"end":491},"obj":"Species"},{"id":"213","span":{"begin":14,"end":17},"obj":"Chemical"},{"id":"214","span":{"begin":139,"end":155},"obj":"Chemical"},{"id":"215","span":{"begin":308,"end":324},"obj":"Chemical"},{"id":"216","span":{"begin":580,"end":584},"obj":"Chemical"},{"id":"217","span":{"begin":925,"end":936},"obj":"Chemical"}],"attributes":[{"id":"A209","pred":"tao:has_database_id","subj":"209","obj":"Gene:134864"},{"id":"A210","pred":"tao:has_database_id","subj":"210","obj":"Gene:134864"},{"id":"A211","pred":"tao:has_database_id","subj":"211","obj":"Gene:134864"},{"id":"A212","pred":"tao:has_database_id","subj":"212","obj":"Tax:562"},{"id":"A214","pred":"tao:has_database_id","subj":"214","obj":"MESH:D000645"},{"id":"A215","pred":"tao:has_database_id","subj":"215","obj":"MESH:D000645"},{"id":"A216","pred":"tao:has_database_id","subj":"216","obj":"MESH:D012492"}],"namespaces":[{"prefix":"Tax","uri":"https://www.ncbi.nlm.nih.gov/taxonomy/"},{"prefix":"MESH","uri":"https://id.nlm.nih.gov/mesh/"},{"prefix":"Gene","uri":"https://www.ncbi.nlm.nih.gov/gene/"},{"prefix":"CVCL","uri":"https://web.expasy.org/cellosaurus/CVCL_"}],"text":"The uncharged PAS moiety, which does not alter the isoelectric point of the target peptide, facilitates classical protein precipitation by ammonium sulfate, thus providing an efficient and inexpensive purification step. After adjusting the cleared whole cell extract prepared by mechanical cell lysis to 30% ammonium sulfate saturation, most of the host cell proteins remained in solution while both PAS-Tα1 and PAS-Tα1 were selectively recovered as a precipitate. To remove residual E. coli proteins, the redissolved precipitate was subjected to ion exchange chromatography on a salt-tolerant anion exchange (AEX) resin at pH 8.5. Even though the PASylated Tα1 peptide with a calculated pI of 4.3 [38] for both versions should be negatively charged under these conditions and, hence, is expected to adsorb to the resin, the recombinant fusion proteins were quantitatively found in the flow-through. Possibly, the voluminous PAS polymer partially shields the small peptide from ionic interactions with the chromatography matrix. Nevertheless, this step resulted in efficient depletion both of residual host cell proteins and of bacterial endotoxins."}

{"project":"LitCovid-sentences","denotations":[{"id":"T58","span":{"begin":0,"end":219},"obj":"Sentence"},{"id":"T59","span":{"begin":220,"end":464},"obj":"Sentence"},{"id":"T60","span":{"begin":465,"end":631},"obj":"Sentence"},{"id":"T61","span":{"begin":632,"end":899},"obj":"Sentence"},{"id":"T62","span":{"begin":900,"end":1028},"obj":"Sentence"},{"id":"T63","span":{"begin":1029,"end":1149},"obj":"Sentence"}],"namespaces":[{"prefix":"_base","uri":"http://pubannotation.org/ontology/tao.owl#"}],"text":"The uncharged PAS moiety, which does not alter the isoelectric point of the target peptide, facilitates classical protein precipitation by ammonium sulfate, thus providing an efficient and inexpensive purification step. After adjusting the cleared whole cell extract prepared by mechanical cell lysis to 30% ammonium sulfate saturation, most of the host cell proteins remained in solution while both PAS-Tα1 and PAS-Tα1 were selectively recovered as a precipitate. To remove residual E. coli proteins, the redissolved precipitate was subjected to ion exchange chromatography on a salt-tolerant anion exchange (AEX) resin at pH 8.5. Even though the PASylated Tα1 peptide with a calculated pI of 4.3 [38] for both versions should be negatively charged under these conditions and, hence, is expected to adsorb to the resin, the recombinant fusion proteins were quantitatively found in the flow-through. Possibly, the voluminous PAS polymer partially shields the small peptide from ionic interactions with the chromatography matrix. Nevertheless, this step resulted in efficient depletion both of residual host cell proteins and of bacterial endotoxins."}