{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"institution":[{"name":"bioRxiv"}],"indexed":{"date-parts":[[2026,8,10]],"date-time":"2026-08-10T20:28:06Z","timestamp":1786393686147,"version":"build-2736575974"},"posted":{"date-parts":[[2026,8,7]]},"group-title":"Biophysics","reference-count":87,"publisher":"openRxiv","license":[{"start":{"date-parts":[[2026,8,7]],"date-time":"2026-08-07T00:00:00Z","timestamp":1786060800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/www.biorxiv.org\/about\/FAQ#license"}],"funder":[{"award":["R35 GM 136632"],"award-info":[{"award-number":["R35 GM 136632"]}],"id":[{"id":"https:\/\/ror.org\/01cwqze88","id-type":"ROR","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"accepted":{"date-parts":[[2026,8,7]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                <jats:p>\n                  UvrD-family Superfamily 1A helicases are processive ATP-dependent motor proteins that function during DNA replication, recombination, repair, and transcription. UvrD-family monomers translocate along single stranded (ss) DNA with 3\u2019-to-5\u2019 directionality but must be activated by dimerization to become helicases in the absence of force or accessory factors.\n                  <jats:italic>Mycobacterium tuberculosis<\/jats:italic>\n                  (\n                  <jats:italic>Mtb<\/jats:italic>\n                  ) UvrD1 helicase forms dimers via a disulfide bond between native cysteines in the 2B sub-domains of each monomer.\n                  <jats:italic>E. coli<\/jats:italic>\n                  UvrD forms non-covalent dimers using the same 2B domain interface as in\n                  <jats:italic>Mtb<\/jats:italic>\n                  UvrD1. Using both ensemble and single DNA molecule approaches we examined an\n                  <jats:italic>E. coli<\/jats:italic>\n                  UvrD variant (R421C), which forms covalent dimers with constitutive helicase activity. For the first time this has enabled us to compare the ssDNA translocation and helicase activities of covalent dimers and monomers. Crosslinked UvrD dimers exhibit much higher ssDNA translocation processivities than monomers, although with similar translocation rates. Crosslinked UvrD dimers also show highly processive DNA unwinding of thousands of base pairs, much higher than non-crosslinked UvrD dimers, while monomers show no DNA unwinding activity. DNA unwinding rates of crosslinked UvrD dimers are only \u223c20% slower than ssDNA translocation rates, indicating they are \u201cactive\u201d helicases that directly facilitate duplex destabilization.\n                <\/jats:p>","DOI":"10.64898\/2026.08.07.743547","type":"posted-content","created":{"date-parts":[[2026,8,8]],"date-time":"2026-08-08T05:10:17Z","timestamp":1786165817000},"source":"Crossref","is-referenced-by-count":0,"title":["Two heads are better than one: Single stranded DNA translocation of UvrD-family dimers vs. monomers"],"prefix":"10.64898","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-2497-1800","authenticated-orcid":false,"given":"Kacey N.","family":"Mersch","sequence":"first","affiliation":[{"name":"Department of Biochemistry and Molecular Biophysics Washington University in St. Louis School of Medicine St. Louis, MO 63110"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5731-8824","authenticated-orcid":false,"given":"Binh","family":"Nguyen","sequence":"additional","affiliation":[{"name":"Department of Biochemistry and Molecular Biophysics Washington University in St. Louis School of Medicine St. Louis, MO 63110"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Alexander G.","family":"Kozlov","sequence":"additional","affiliation":[{"name":"Department of Biochemistry and Molecular Biophysics Washington University in St. Louis School of Medicine St. Louis, MO 63110"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6616-2967","authenticated-orcid":false,"given":"Timothy M.","family":"Lohman","sequence":"additional","affiliation":[{"name":"Department of Biochemistry and Molecular Biophysics Washington University in St. Louis School of Medicine St. Louis, MO 63110"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"54368","reference":[{"key":"2026081012301119000_2026.08.07.743547v1.1","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.2422330122"},{"key":"2026081012301119000_2026.08.07.743547v1.2","doi-asserted-by":"publisher","DOI":"10.1146\/annurev.bi.65.070196.001125"},{"key":"2026081012301119000_2026.08.07.743547v1.3","doi-asserted-by":"publisher","DOI":"10.1146\/annurev.biochem.69.1.651"},{"key":"2026081012301119000_2026.08.07.743547v1.4","doi-asserted-by":"publisher","DOI":"10.1146\/annurev.biophys.37.032807.125908"},{"key":"2026081012301119000_2026.08.07.743547v1.5","doi-asserted-by":"crossref","unstructured":"Brosh RM, Jr ., Matson SW . 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