High-risk (HPV16) human papillomavirus E7 oncoprotein is highly stable and extended, with conformational transitions that could explain its multiple cellular binding partners

High-risk papillomaviruses are known to exert their transforming activity mainly through E7, one of their two oncoproteins. Despite its relevance, no structural information has been obtained that could explain the apparent broad binding specificity of E7. Recombinant E7 from HPV-16 purified to near...

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Autores principales:	Alonso, Leonardo, García Alai, María, Nadra, Alejandro Daniel, de Prat Gay, Gonzalo
Publicado:	2002
Materias:	Hydrophobic surfaces Conformations Dimers Hydrodynamics Light scattering Molecular weight Proteins Biochemistry oncoprotein article binding affinity circular dichroism conformational transition gel filtration chromatography hydrodynamics light scattering molecular weight nonhuman priority journal protein binding protein conformation protein denaturation protein protein interaction protein purification protein stability protein structure spectral sensitivity structure analysis Wart virus Anilino Naphthalenesulfonates Cell Transformation, Viral Circular Dichroism Dimerization Electrophoresis, Polyacrylamide Gel Guanidine Heat Humans Hydrogen-Ion Concentration Hydrophobicity Oncogene Proteins, Viral Papillomaviridae Protein Binding Protein Conformation Protein Denaturation Protein Folding Risk Factors Sodium Dodecyl Sulfate Solvents DNA viruses Human papillomavirus Human papillomavirus type 16 Human papillomavirus types Papillomavirus Papovaviridae
Acceso en línea:	https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00062960_v41_n33_p10510_Alonso http://hdl.handle.net/20.500.12110/paper_00062960_v41_n33_p10510_Alonso
Aporte de:	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires

id	paper:paper_00062960_v41_n33_p10510_Alonso
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spelling	paper:paper_00062960_v41_n33_p10510_Alonso2023-06-08T14:30:39Z High-risk (HPV16) human papillomavirus E7 oncoprotein is highly stable and extended, with conformational transitions that could explain its multiple cellular binding partners Alonso, Leonardo García Alai, María Nadra, Alejandro Daniel de Prat Gay, Gonzalo Hydrophobic surfaces Conformations Dimers Hydrodynamics Light scattering Molecular weight Proteins Biochemistry oncoprotein article binding affinity circular dichroism conformational transition gel filtration chromatography hydrodynamics light scattering molecular weight nonhuman priority journal protein binding protein conformation protein denaturation protein protein interaction protein purification protein stability protein structure spectral sensitivity structure analysis Wart virus Anilino Naphthalenesulfonates Cell Transformation, Viral Circular Dichroism Dimerization Electrophoresis, Polyacrylamide Gel Guanidine Heat Humans Hydrogen-Ion Concentration Hydrophobicity Oncogene Proteins, Viral Papillomaviridae Protein Binding Protein Conformation Protein Denaturation Protein Folding Risk Factors Sodium Dodecyl Sulfate Solvents DNA viruses Human papillomavirus Human papillomavirus type 16 Human papillomavirus types Papillomavirus Papovaviridae High-risk papillomaviruses are known to exert their transforming activity mainly through E7, one of their two oncoproteins. Despite its relevance, no structural information has been obtained that could explain the apparent broad binding specificity of E7. Recombinant E7 from HPV-16 purified to near homogeneity showed two species in gel filtration chromatography, one of these corresponding to a dimer with a molecular weight of 22 kDa, determined by multiangle light scattering. The E7 dimer was isolated for characterization and was shown to undergo a substantial conformational transition when changing from pH 7.0 to 5.0, with an increase in helical structure and increased solvent accessibility to hydrophobic surfaces. The protein was resistant to thermal denaturation even in the presence of SDS, and we show that persistent residual structure in the monomer is responsible for its reported anomalous electrophoretic behavior. The dimer also displays a nonglobular hydrodynamic volume based on gel filtration experiments and becomes more globular in the presence of 0.3 M guanidinium chloride, with hydrophobic surfaces becoming accessible to the solvent, as indicated by the large increase in ANS binding. At low protein concentration, dissociation of the globular E7 dimer was observed, preceding the cooperative unfolding of the structured and extended monomer. Although E7 bears properties that resemble natively unfolded polypeptides, its far-UV circular dichroism spectrum, cooperative unfolding, and exposure of ANS binding sites support a folded and extended, as opposed to disordered and fluctuating, conformation. The large increase in solvent accessibility to hydrophobic surfaces upon small pH decrease within physiological range and in mild denaturant concentrations suggests conformational properties that could have evolved to enable protein-protein recognition of the large number of cellular binding partners reported. Fil:Alonso, L.G. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:García-Alai, M.M. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Nadra, A.D. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:De Prat-Gay, G. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. 2002 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00062960_v41_n33_p10510_Alonso http://hdl.handle.net/20.500.12110/paper_00062960_v41_n33_p10510_Alonso
institution	Universidad de Buenos Aires
institution_str	I-28
repository_str	R-134
collection	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic	Hydrophobic surfaces Conformations Dimers Hydrodynamics Light scattering Molecular weight Proteins Biochemistry oncoprotein article binding affinity circular dichroism conformational transition gel filtration chromatography hydrodynamics light scattering molecular weight nonhuman priority journal protein binding protein conformation protein denaturation protein protein interaction protein purification protein stability protein structure spectral sensitivity structure analysis Wart virus Anilino Naphthalenesulfonates Cell Transformation, Viral Circular Dichroism Dimerization Electrophoresis, Polyacrylamide Gel Guanidine Heat Humans Hydrogen-Ion Concentration Hydrophobicity Oncogene Proteins, Viral Papillomaviridae Protein Binding Protein Conformation Protein Denaturation Protein Folding Risk Factors Sodium Dodecyl Sulfate Solvents DNA viruses Human papillomavirus Human papillomavirus type 16 Human papillomavirus types Papillomavirus Papovaviridae
spellingShingle	Hydrophobic surfaces Conformations Dimers Hydrodynamics Light scattering Molecular weight Proteins Biochemistry oncoprotein article binding affinity circular dichroism conformational transition gel filtration chromatography hydrodynamics light scattering molecular weight nonhuman priority journal protein binding protein conformation protein denaturation protein protein interaction protein purification protein stability protein structure spectral sensitivity structure analysis Wart virus Anilino Naphthalenesulfonates Cell Transformation, Viral Circular Dichroism Dimerization Electrophoresis, Polyacrylamide Gel Guanidine Heat Humans Hydrogen-Ion Concentration Hydrophobicity Oncogene Proteins, Viral Papillomaviridae Protein Binding Protein Conformation Protein Denaturation Protein Folding Risk Factors Sodium Dodecyl Sulfate Solvents DNA viruses Human papillomavirus Human papillomavirus type 16 Human papillomavirus types Papillomavirus Papovaviridae Alonso, Leonardo García Alai, María Nadra, Alejandro Daniel de Prat Gay, Gonzalo High-risk (HPV16) human papillomavirus E7 oncoprotein is highly stable and extended, with conformational transitions that could explain its multiple cellular binding partners
topic_facet	Hydrophobic surfaces Conformations Dimers Hydrodynamics Light scattering Molecular weight Proteins Biochemistry oncoprotein article binding affinity circular dichroism conformational transition gel filtration chromatography hydrodynamics light scattering molecular weight nonhuman priority journal protein binding protein conformation protein denaturation protein protein interaction protein purification protein stability protein structure spectral sensitivity structure analysis Wart virus Anilino Naphthalenesulfonates Cell Transformation, Viral Circular Dichroism Dimerization Electrophoresis, Polyacrylamide Gel Guanidine Heat Humans Hydrogen-Ion Concentration Hydrophobicity Oncogene Proteins, Viral Papillomaviridae Protein Binding Protein Conformation Protein Denaturation Protein Folding Risk Factors Sodium Dodecyl Sulfate Solvents DNA viruses Human papillomavirus Human papillomavirus type 16 Human papillomavirus types Papillomavirus Papovaviridae
description	High-risk papillomaviruses are known to exert their transforming activity mainly through E7, one of their two oncoproteins. Despite its relevance, no structural information has been obtained that could explain the apparent broad binding specificity of E7. Recombinant E7 from HPV-16 purified to near homogeneity showed two species in gel filtration chromatography, one of these corresponding to a dimer with a molecular weight of 22 kDa, determined by multiangle light scattering. The E7 dimer was isolated for characterization and was shown to undergo a substantial conformational transition when changing from pH 7.0 to 5.0, with an increase in helical structure and increased solvent accessibility to hydrophobic surfaces. The protein was resistant to thermal denaturation even in the presence of SDS, and we show that persistent residual structure in the monomer is responsible for its reported anomalous electrophoretic behavior. The dimer also displays a nonglobular hydrodynamic volume based on gel filtration experiments and becomes more globular in the presence of 0.3 M guanidinium chloride, with hydrophobic surfaces becoming accessible to the solvent, as indicated by the large increase in ANS binding. At low protein concentration, dissociation of the globular E7 dimer was observed, preceding the cooperative unfolding of the structured and extended monomer. Although E7 bears properties that resemble natively unfolded polypeptides, its far-UV circular dichroism spectrum, cooperative unfolding, and exposure of ANS binding sites support a folded and extended, as opposed to disordered and fluctuating, conformation. The large increase in solvent accessibility to hydrophobic surfaces upon small pH decrease within physiological range and in mild denaturant concentrations suggests conformational properties that could have evolved to enable protein-protein recognition of the large number of cellular binding partners reported.
author	Alonso, Leonardo García Alai, María Nadra, Alejandro Daniel de Prat Gay, Gonzalo
author_facet	Alonso, Leonardo García Alai, María Nadra, Alejandro Daniel de Prat Gay, Gonzalo
author_sort	Alonso, Leonardo
title	High-risk (HPV16) human papillomavirus E7 oncoprotein is highly stable and extended, with conformational transitions that could explain its multiple cellular binding partners
title_short	High-risk (HPV16) human papillomavirus E7 oncoprotein is highly stable and extended, with conformational transitions that could explain its multiple cellular binding partners
title_full	High-risk (HPV16) human papillomavirus E7 oncoprotein is highly stable and extended, with conformational transitions that could explain its multiple cellular binding partners
title_fullStr	High-risk (HPV16) human papillomavirus E7 oncoprotein is highly stable and extended, with conformational transitions that could explain its multiple cellular binding partners
title_full_unstemmed	High-risk (HPV16) human papillomavirus E7 oncoprotein is highly stable and extended, with conformational transitions that could explain its multiple cellular binding partners
title_sort	high-risk (hpv16) human papillomavirus e7 oncoprotein is highly stable and extended, with conformational transitions that could explain its multiple cellular binding partners
publishDate	2002
url	https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00062960_v41_n33_p10510_Alonso http://hdl.handle.net/20.500.12110/paper_00062960_v41_n33_p10510_Alonso
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_version_	1768544484083105792

High-risk (HPV16) human papillomavirus E7 oncoprotein is highly stable and extended, with conformational transitions that could explain its multiple cellular binding partners

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