{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"institution":[{"name":"bioRxiv"}],"indexed":{"date-parts":[[2026,7,30]],"date-time":"2026-07-30T17:08:47Z","timestamp":1785431327585,"version":"3.56.0"},"posted":{"date-parts":[[2026,6,10]]},"group-title":"Biophysics","reference-count":8,"publisher":"openRxiv","license":[{"start":{"date-parts":[[2026,6,10]],"date-time":"2026-06-10T00:00:00Z","timestamp":1781049600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/www.biorxiv.org\/about\/FAQ#license"}],"funder":[{"award":["24-SI-006"],"award-info":[{"award-number":["24-SI-006"]}],"id":[{"id":"https:\/\/ror.org\/041nk4h53","id-type":"ROR","asserted-by":"publisher"}]},{"DOI":"10.13039\/100000002","name":"National Institutes of Health","doi-asserted-by":"crossref","award":["U19 AI144184"],"award-info":[{"award-number":["U19 AI144184"]}],"id":[{"id":"10.13039\/100000002","id-type":"DOI","asserted-by":"crossref"}]},{"name":"Department of War\u2019s Chemical and Biological Defense Program"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"accepted":{"date-parts":[[2026,6,10]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                <jats:p>\n                  We demonstrate the use of fluorescence correlation spectroscopy (FCS) to characterize fluorescently-labeled protein production. We use cell-free protein synthesis to express the protein YFP-CopB, a fusion of Chlamydia Outer Protein (Cop) B and Yellow Fluorescent Protein (YFP). CopB is a \u223c50 kDa protein believed to have a critical role in chlamydial infection.\n                  <jats:sup>1<\/jats:sup>\n                  After adding a plasmid encoding YFP-CopB to an E. coli cell-free lysate, protein expression begins. We track the cell-free reaction over several hours using the EI-FLEX, a commercial instrument with FCS capability. As protein is expressed over time, YFP-CopB increases in concentration, and the EI-FLEX detects an increase in fluorescent signal above the background of the cell-free lysate. The FCS data collected gives information about the size, aggregation tendencies, rates of production and fluorescent protein maturation, and concentration of the YFP-CopB produced. The use of FCS concurrent with cell-free synthesis presents a simple method to characterize proteins of interest as they are produced without the need for purification.\n                <\/jats:p>","DOI":"10.64898\/2026.06.07.728995","type":"posted-content","created":{"date-parts":[[2026,6,11]],"date-time":"2026-06-11T01:00:18Z","timestamp":1781139618000},"source":"Crossref","is-referenced-by-count":0,"title":["Fluorescence correlation spectroscopy measurements of the chlamydia outer protein B (CopB) made by cell-free protein synthesis"],"prefix":"10.64898","author":[{"given":"Emma","family":"Laurence","sequence":"first","affiliation":[{"name":"Physical and Life Sciences, Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, CA 94550"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Shakiba","family":"Nikfarjam","sequence":"additional","affiliation":[{"name":"Physical and Life Sciences, Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, CA 94550"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Steven","family":"Hoang-Phou","sequence":"additional","affiliation":[{"name":"Physical and Life Sciences, Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, CA 94550"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ted","family":"Laurence","sequence":"additional","affiliation":[{"name":"Physical and Life Sciences, Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, CA 94550"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Matt","family":"Coleman","sequence":"additional","affiliation":[{"name":"Physical and Life Sciences, Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, CA 94550"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0057-3397","authenticated-orcid":false,"given":"Chao","family":"Liu","sequence":"additional","affiliation":[{"name":"Physical and Life Sciences, Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, CA 94550"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"54368","reference":[{"key":"2026061310452426000_2026.06.07.728995v1.1","doi-asserted-by":"publisher","DOI":"10.1186\/s12866-015-0498-1"},{"key":"2026061310452426000_2026.06.07.728995v1.2","doi-asserted-by":"publisher","DOI":"10.1002\/bip.1974.360130102"},{"key":"2026061310452426000_2026.06.07.728995v1.3","doi-asserted-by":"publisher","DOI":"10.1021\/acs.analchem.4c05485"},{"key":"2026061310452426000_2026.06.07.728995v1.4","doi-asserted-by":"publisher","DOI":"10.1016\/j.ab.2011.10.040"},{"key":"2026061310452426000_2026.06.07.728995v1.5","doi-asserted-by":"publisher","DOI":"10.1038\/nbt.1556"},{"key":"2026061310452426000_2026.06.07.728995v1.6","doi-asserted-by":"publisher","DOI":"10.1098\/rsfs.2013.0018"},{"key":"2026061310452426000_2026.06.07.728995v1.7","unstructured":"Buschmann, V. ; Kr\u00e4mer, B. ; Koberling, F. ; GmbH, P. ; Macdonald, R. ; R\u00fcttinger, S. Quantitative FCS: Determination of the Confocal Volume by FCS and Bead Scanning with the MicroTime 200."},{"key":"2026061310452426000_2026.06.07.728995v1.8","doi-asserted-by":"publisher","DOI":"10.1007\/s00232-024-00333-0"}],"container-title":[],"original-title":[],"link":[{"URL":"https:\/\/syndication.highwire.org\/content\/doi\/10.64898\/2026.06.07.728995","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,6,13]],"date-time":"2026-06-13T17:45:44Z","timestamp":1781372744000},"score":1,"resource":{"primary":{"URL":"http:\/\/biorxiv.org\/lookup\/doi\/10.64898\/2026.06.07.728995"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,6,10]]},"references-count":8,"URL":"https:\/\/doi.org\/10.64898\/2026.06.07.728995","relation":{},"subject":[],"published":{"date-parts":[[2026,6,10]]},"subtype":"preprint"}}