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Protein Folding Absent Selection
Biological proteins are known to fold into specific 3D conformations. However, the fundamental question has remained: Do they fold because they are biological, and evolution has selected sequences which fold? Or is folding a common trait, widespread throughout sequence space? To address this questio...
Autores principales: | , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
MDPI
2011
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3927614/ https://www.ncbi.nlm.nih.gov/pubmed/24710212 http://dx.doi.org/10.3390/genes2030608 |
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author | LaBean, Thomas H. Butt, Tauseef R. Kauffman, Stuart A. Schultes, Erik A. |
author_facet | LaBean, Thomas H. Butt, Tauseef R. Kauffman, Stuart A. Schultes, Erik A. |
author_sort | LaBean, Thomas H. |
collection | PubMed |
description | Biological proteins are known to fold into specific 3D conformations. However, the fundamental question has remained: Do they fold because they are biological, and evolution has selected sequences which fold? Or is folding a common trait, widespread throughout sequence space? To address this question arbitrary, unevolved, random-sequence proteins were examined for structural features found in folded, biological proteins. Libraries of long (71 residue), random-sequence polypeptides, with ensemble amino acid composition near the mean for natural globular proteins, were expressed as cleavable fusions with ubiquitin. The structural properties of both the purified pools and individual isolates were then probed using circular dichroism, fluorescence emission, and fluorescence quenching techniques. Despite this necessarily sparse “sampling” of sequence space, structural properties that define globular biological proteins, namely collapsed conformations, secondary structure, and cooperative unfolding, were found to be prevalent among unevolved sequences. Thus, for polypeptides the size of small proteins, natural selection is not necessary to account for the compact and cooperative folded states observed in nature. |
format | Online Article Text |
id | pubmed-3927614 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2011 |
publisher | MDPI |
record_format | MEDLINE/PubMed |
spelling | pubmed-39276142014-03-26 Protein Folding Absent Selection LaBean, Thomas H. Butt, Tauseef R. Kauffman, Stuart A. Schultes, Erik A. Genes (Basel) Article Biological proteins are known to fold into specific 3D conformations. However, the fundamental question has remained: Do they fold because they are biological, and evolution has selected sequences which fold? Or is folding a common trait, widespread throughout sequence space? To address this question arbitrary, unevolved, random-sequence proteins were examined for structural features found in folded, biological proteins. Libraries of long (71 residue), random-sequence polypeptides, with ensemble amino acid composition near the mean for natural globular proteins, were expressed as cleavable fusions with ubiquitin. The structural properties of both the purified pools and individual isolates were then probed using circular dichroism, fluorescence emission, and fluorescence quenching techniques. Despite this necessarily sparse “sampling” of sequence space, structural properties that define globular biological proteins, namely collapsed conformations, secondary structure, and cooperative unfolding, were found to be prevalent among unevolved sequences. Thus, for polypeptides the size of small proteins, natural selection is not necessary to account for the compact and cooperative folded states observed in nature. MDPI 2011-08-16 /pmc/articles/PMC3927614/ /pubmed/24710212 http://dx.doi.org/10.3390/genes2030608 Text en © 2011 by the authors; licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution license (http://creativecommons.org/licenses/by/3.0/). |
spellingShingle | Article LaBean, Thomas H. Butt, Tauseef R. Kauffman, Stuart A. Schultes, Erik A. Protein Folding Absent Selection |
title | Protein Folding Absent Selection |
title_full | Protein Folding Absent Selection |
title_fullStr | Protein Folding Absent Selection |
title_full_unstemmed | Protein Folding Absent Selection |
title_short | Protein Folding Absent Selection |
title_sort | protein folding absent selection |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3927614/ https://www.ncbi.nlm.nih.gov/pubmed/24710212 http://dx.doi.org/10.3390/genes2030608 |
work_keys_str_mv | AT labeanthomash proteinfoldingabsentselection AT butttauseefr proteinfoldingabsentselection AT kauffmanstuarta proteinfoldingabsentselection AT schulteserika proteinfoldingabsentselection |