Improved affinity at the cost of decreased specificity: a recurring theme in PDZ-peptide interactions

The E6 protein from human papillomavirus (HPV) plays an important role during productive infection and is a potential drug target. We have previously designed a high affinity bivalent protein binder for the E6 protein, a fusion between a helix from the E6 associated protein and PDZØ9, an engineered...

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Main Authors:	Karlsson, O. Andreas, Sundell, Gustav N., Andersson, Eva, Ivarsson, Ylva, Jemth, Per
Format:	Online
Language:	English
Published:	Nature Publishing Group 2016
Online Access:	https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5046105/

id	pubmed-5046105
recordtype	oai_dc
spelling	pubmed-50461052016-10-11 Improved affinity at the cost of decreased specificity: a recurring theme in PDZ-peptide interactions Karlsson, O. Andreas Sundell, Gustav N. Andersson, Eva Ivarsson, Ylva Jemth, Per Article The E6 protein from human papillomavirus (HPV) plays an important role during productive infection and is a potential drug target. We have previously designed a high affinity bivalent protein binder for the E6 protein, a fusion between a helix from the E6 associated protein and PDZØ9, an engineered variant (L391F/K392M) of the second PDZ domain from synapse associated protein 97 (SAP97 PDZ2). How the substitutions improve the affinity of SAP97 PDZ2 for HPV E6 is not clear and it is not known to what extent they affect the specificity for cellular targets. Here, we explore the specificity of wild type SAP97 PDZ2 and PDZØ9 through proteomic peptide phage display. In addition, we employ a double mutant cycle of SAP97 PDZ2 in which the binding kinetics for nine identified potential cellular peptide ligands are measured and compared with those for the C-terminal E6 peptide. The results demonstrate that PDZØ9 has an increased affinity for all peptides, but at the cost of specificity. Furthermore, there is a peptide dependent coupling free energy between the side chains at positions 391 and 392. This corroborates our previous allosteric model for PDZ domains, involving sampling of intramolecular energetic pathways. Nature Publishing Group 2016-10-03 /pmc/articles/PMC5046105/ /pubmed/27694853 http://dx.doi.org/10.1038/srep34269 Text en Copyright © 2016, The Author(s) http://creativecommons.org/licenses/by/4.0/ This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/
repository_type	Open Access Journal
institution_category	Foreign Institution
institution	US National Center for Biotechnology Information
building	NCBI PubMed
collection	Online Access
language	English
format	Online
author	Karlsson, O. Andreas Sundell, Gustav N. Andersson, Eva Ivarsson, Ylva Jemth, Per
spellingShingle	Karlsson, O. Andreas Sundell, Gustav N. Andersson, Eva Ivarsson, Ylva Jemth, Per Improved affinity at the cost of decreased specificity: a recurring theme in PDZ-peptide interactions
author_facet	Karlsson, O. Andreas Sundell, Gustav N. Andersson, Eva Ivarsson, Ylva Jemth, Per
author_sort	Karlsson, O. Andreas
title	Improved affinity at the cost of decreased specificity: a recurring theme in PDZ-peptide interactions
title_short	Improved affinity at the cost of decreased specificity: a recurring theme in PDZ-peptide interactions
title_full	Improved affinity at the cost of decreased specificity: a recurring theme in PDZ-peptide interactions
title_fullStr	Improved affinity at the cost of decreased specificity: a recurring theme in PDZ-peptide interactions
title_full_unstemmed	Improved affinity at the cost of decreased specificity: a recurring theme in PDZ-peptide interactions
title_sort	improved affinity at the cost of decreased specificity: a recurring theme in pdz-peptide interactions
description	The E6 protein from human papillomavirus (HPV) plays an important role during productive infection and is a potential drug target. We have previously designed a high affinity bivalent protein binder for the E6 protein, a fusion between a helix from the E6 associated protein and PDZØ9, an engineered variant (L391F/K392M) of the second PDZ domain from synapse associated protein 97 (SAP97 PDZ2). How the substitutions improve the affinity of SAP97 PDZ2 for HPV E6 is not clear and it is not known to what extent they affect the specificity for cellular targets. Here, we explore the specificity of wild type SAP97 PDZ2 and PDZØ9 through proteomic peptide phage display. In addition, we employ a double mutant cycle of SAP97 PDZ2 in which the binding kinetics for nine identified potential cellular peptide ligands are measured and compared with those for the C-terminal E6 peptide. The results demonstrate that PDZØ9 has an increased affinity for all peptides, but at the cost of specificity. Furthermore, there is a peptide dependent coupling free energy between the side chains at positions 391 and 392. This corroborates our previous allosteric model for PDZ domains, involving sampling of intramolecular energetic pathways.
publisher	Nature Publishing Group
publishDate	2016
url	https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5046105/
_version_	1613669311862276096

Improved affinity at the cost of decreased specificity: a recurring theme in PDZ-peptide interactions

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