{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,12]],"date-time":"2025-10-12T01:50:49Z","timestamp":1760233849577,"version":"build-2065373602"},"reference-count":54,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2021,2,26]],"date-time":"2021-02-26T00:00:00Z","timestamp":1614297600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Funda\u00e7\u00e3o para a Ci\u00eancia e a Tecnologia, Portugal","award":["UID\/Multi\/04326\/2019"],"award-info":[{"award-number":["UID\/Multi\/04326\/2019"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Biomolecules"],"abstract":"<jats:p>We investigate the hypothesis that protein folding is a kinetic, non-equilibrium process, in which the structure of the nascent chain is crucial. We compare actual amino acid frequencies in loops, \u03b1-helices and \u03b2-sheets with the frequencies that would arise in the absence of any amino acid bias for those secondary structures. The novel analysis suggests that while specific amino acids exist to drive the formation of loops and sheets, none stand out as drivers for \u03b1-helices. This favours the idea that the \u03b1-helix is the initial structure of most proteins before the folding process begins.<\/jats:p>","DOI":"10.3390\/biom11030357","type":"journal-article","created":{"date-parts":[[2021,2,26]],"date-time":"2021-02-26T09:47:20Z","timestamp":1614332840000},"page":"357","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":2,"title":["Statistical Evidence for a Helical Nascent Chain"],"prefix":"10.3390","volume":"11","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-7958-6435","authenticated-orcid":false,"given":"Leonor","family":"Cruzeiro","sequence":"first","affiliation":[{"name":"CCMAR\/CIMAR\u2014Centro de Ci\u00eancias do Mar, FCT, Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5201-9473","authenticated-orcid":false,"given":"Andrew C.","family":"Gill","sequence":"additional","affiliation":[{"name":"School of Chemistry, Joseph Banks Laboratories, University of Lincoln, Green Lane, Lincoln LN67DL, UK"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9884-9093","authenticated-orcid":false,"given":"J. Chris","family":"Eilbeck","sequence":"additional","affiliation":[{"name":"Department of Mathematics and Maxwell Institute, Heriot-Watt University, Edinburgh EH14 4AS, UK"}]}],"member":"1968","published-online":{"date-parts":[[2021,2,26]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"211","DOI":"10.1021\/bi00699a001","article-title":"Conformational Parameters for Amino Acids in Helical, \u03b2-Sheet, and Random Coil Regions Calculated from Proteins","volume":"3","author":"Chou","year":"1974","journal-title":"Biochemistry"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"1839","DOI":"10.1016\/S0021-9258(19)73945-3","article-title":"Side-chain interactions governing the pairing of half-cystine residues in ribonuclease","volume":"237","author":"Haber","year":"1962","journal-title":"J. Biol. 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