How the biotin-streptavidin interaction was made even stronger: investigation via crystallography and a chimaeric tetramer
The interaction between SA (streptavidin) and biotin is one of the strongest non-covalent interactions in Nature. SA is a widely used tool and a paradigm for protein-ligand interactions. We previously developed a SA mutant, termed Tr (treptavidin), possessing a 10-fold lower off-rate for biotin, wit...
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Format: | Journal article |
Language: | English |
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Portland Press Ltd.
2011
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author | Chivers, C Koner, A Lowe, E Howarth, M |
author_facet | Chivers, C Koner, A Lowe, E Howarth, M |
author_sort | Chivers, C |
collection | OXFORD |
description | The interaction between SA (streptavidin) and biotin is one of the strongest non-covalent interactions in Nature. SA is a widely used tool and a paradigm for protein-ligand interactions. We previously developed a SA mutant, termed Tr (treptavidin), possessing a 10-fold lower off-rate for biotin, with increased mechanical and thermal stability. In the present study, we determined the crystal structures of apo-Tr at 1.5 Å resolution. In apo-SA the loop (L3/4), near biotin's valeryl tail, is typically disordered and open, but closes upon biotin binding. In contrast, L3/4 was shut in both apo-Tr and biotin-Tr. The reduced flexibility of L3/4 and decreased conformational change on biotin binding provide an explanation for Tr's reduced biotin off- and on-rates. L3/4 includes Ser<sup>45</sup>, which forms a hydrogen bond to biotin consistently in Tr, but erratically in SA. Reduced breakage of the biotin-Ser<sup>45</sup> hydrogen bond in Tr is likely to inhibit the initiating event in biotin's dissociation pathway. We generated a Tr with a single biotin-binding site rather than four, which showed a similarly low off-rate, demonstrating that Tr's low off-rate was governed by intrasubunit effects. Understanding the structural features of this tenacious interaction may assist the design of even stronger affinity tags and inhibitors. |
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format | Journal article |
id | oxford-uuid:8a51a274-44f6-4d0d-b41a-4a26d96215e0 |
institution | University of Oxford |
language | English |
last_indexed | 2024-03-07T01:02:55Z |
publishDate | 2011 |
publisher | Portland Press Ltd. |
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spelling | oxford-uuid:8a51a274-44f6-4d0d-b41a-4a26d96215e02022-03-26T22:30:46ZHow the biotin-streptavidin interaction was made even stronger: investigation via crystallography and a chimaeric tetramerJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:8a51a274-44f6-4d0d-b41a-4a26d96215e0BiochemistryEnglishOxford University Research Archive - ValetPortland Press Ltd.2011Chivers, CKoner, ALowe, EHowarth, MThe interaction between SA (streptavidin) and biotin is one of the strongest non-covalent interactions in Nature. SA is a widely used tool and a paradigm for protein-ligand interactions. We previously developed a SA mutant, termed Tr (treptavidin), possessing a 10-fold lower off-rate for biotin, with increased mechanical and thermal stability. In the present study, we determined the crystal structures of apo-Tr at 1.5 Å resolution. In apo-SA the loop (L3/4), near biotin's valeryl tail, is typically disordered and open, but closes upon biotin binding. In contrast, L3/4 was shut in both apo-Tr and biotin-Tr. The reduced flexibility of L3/4 and decreased conformational change on biotin binding provide an explanation for Tr's reduced biotin off- and on-rates. L3/4 includes Ser<sup>45</sup>, which forms a hydrogen bond to biotin consistently in Tr, but erratically in SA. Reduced breakage of the biotin-Ser<sup>45</sup> hydrogen bond in Tr is likely to inhibit the initiating event in biotin's dissociation pathway. We generated a Tr with a single biotin-binding site rather than four, which showed a similarly low off-rate, demonstrating that Tr's low off-rate was governed by intrasubunit effects. Understanding the structural features of this tenacious interaction may assist the design of even stronger affinity tags and inhibitors. |
spellingShingle | Biochemistry Chivers, C Koner, A Lowe, E Howarth, M How the biotin-streptavidin interaction was made even stronger: investigation via crystallography and a chimaeric tetramer |
title | How the biotin-streptavidin interaction was made even stronger: investigation via crystallography and a chimaeric tetramer |
title_full | How the biotin-streptavidin interaction was made even stronger: investigation via crystallography and a chimaeric tetramer |
title_fullStr | How the biotin-streptavidin interaction was made even stronger: investigation via crystallography and a chimaeric tetramer |
title_full_unstemmed | How the biotin-streptavidin interaction was made even stronger: investigation via crystallography and a chimaeric tetramer |
title_short | How the biotin-streptavidin interaction was made even stronger: investigation via crystallography and a chimaeric tetramer |
title_sort | how the biotin streptavidin interaction was made even stronger investigation via crystallography and a chimaeric tetramer |
topic | Biochemistry |
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