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Metal Binding Properties of the N-Terminus of the Functional Amyloid Orb2

The cytoplasmic polyadenylation element binding protein (CPEB) homologue Orb2 is a functional amyloid that plays a key regulatory role for long-term memory in Drosophila. Orb2 has a glutamine, histidine-rich (Q/H-rich) domain that resembles the Q/H-rich, metal binding domain of the Hpn-like protein...

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Autores principales: Bajakian, Thalia H., Cervantes, Silvia A., Soria, Maria A., Beaugrand, Maïwenn, Kim, Ji Yun, Service, Rachel J., Siemer, Ansgar B.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2017
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5618238/
https://www.ncbi.nlm.nih.gov/pubmed/28763009
http://dx.doi.org/10.3390/biom7030057
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author Bajakian, Thalia H.
Cervantes, Silvia A.
Soria, Maria A.
Beaugrand, Maïwenn
Kim, Ji Yun
Service, Rachel J.
Siemer, Ansgar B.
author_facet Bajakian, Thalia H.
Cervantes, Silvia A.
Soria, Maria A.
Beaugrand, Maïwenn
Kim, Ji Yun
Service, Rachel J.
Siemer, Ansgar B.
author_sort Bajakian, Thalia H.
collection PubMed
description The cytoplasmic polyadenylation element binding protein (CPEB) homologue Orb2 is a functional amyloid that plays a key regulatory role for long-term memory in Drosophila. Orb2 has a glutamine, histidine-rich (Q/H-rich) domain that resembles the Q/H-rich, metal binding domain of the Hpn-like protein (Hpnl) found in Helicobacter pylori. In the present study, we used chromatography and isothermal titration calorimetry (ITC) to show that the Q/H-rich domain of Orb2 binds Ni(2+) and other transition metals ions with μM affinity. Using site directed mutagenesis, we show that several histidine residues are important for binding. In particular, the H61Y mutation, which was previously shown to affect the aggregation of Orb2 in cell culture, completely inhibited metal binding of Orb2. Finally, we used thioflavin T fluorescence and electron microscopy images to show that Ni(2+) binding induces the aggregating of Orb2 into structures that are distinct from the amyloid fibrils formed in the absence of Ni(2+). These data suggest that transition metal binding might be important for the function of Orb2 and potentially long-term memory in Drosophila.
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spelling pubmed-56182382017-09-29 Metal Binding Properties of the N-Terminus of the Functional Amyloid Orb2 Bajakian, Thalia H. Cervantes, Silvia A. Soria, Maria A. Beaugrand, Maïwenn Kim, Ji Yun Service, Rachel J. Siemer, Ansgar B. Biomolecules Article The cytoplasmic polyadenylation element binding protein (CPEB) homologue Orb2 is a functional amyloid that plays a key regulatory role for long-term memory in Drosophila. Orb2 has a glutamine, histidine-rich (Q/H-rich) domain that resembles the Q/H-rich, metal binding domain of the Hpn-like protein (Hpnl) found in Helicobacter pylori. In the present study, we used chromatography and isothermal titration calorimetry (ITC) to show that the Q/H-rich domain of Orb2 binds Ni(2+) and other transition metals ions with μM affinity. Using site directed mutagenesis, we show that several histidine residues are important for binding. In particular, the H61Y mutation, which was previously shown to affect the aggregation of Orb2 in cell culture, completely inhibited metal binding of Orb2. Finally, we used thioflavin T fluorescence and electron microscopy images to show that Ni(2+) binding induces the aggregating of Orb2 into structures that are distinct from the amyloid fibrils formed in the absence of Ni(2+). These data suggest that transition metal binding might be important for the function of Orb2 and potentially long-term memory in Drosophila. MDPI 2017-08-01 /pmc/articles/PMC5618238/ /pubmed/28763009 http://dx.doi.org/10.3390/biom7030057 Text en © 2017 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 (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Bajakian, Thalia H.
Cervantes, Silvia A.
Soria, Maria A.
Beaugrand, Maïwenn
Kim, Ji Yun
Service, Rachel J.
Siemer, Ansgar B.
Metal Binding Properties of the N-Terminus of the Functional Amyloid Orb2
title Metal Binding Properties of the N-Terminus of the Functional Amyloid Orb2
title_full Metal Binding Properties of the N-Terminus of the Functional Amyloid Orb2
title_fullStr Metal Binding Properties of the N-Terminus of the Functional Amyloid Orb2
title_full_unstemmed Metal Binding Properties of the N-Terminus of the Functional Amyloid Orb2
title_short Metal Binding Properties of the N-Terminus of the Functional Amyloid Orb2
title_sort metal binding properties of the n-terminus of the functional amyloid orb2
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5618238/
https://www.ncbi.nlm.nih.gov/pubmed/28763009
http://dx.doi.org/10.3390/biom7030057
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