An Order-Disorder Transition Plays a Role in Switching Off the Root Effect in Fish Hemoglobins*
The Root effect is a widespread property among fish hemoglobins whose structural basis remains largely obscure. Here we report a crystallographic and spectroscopic characterization of the non-Root-effect hemoglobin isolated from the Antarctic fish Trematomus newnesi in the deoxygenated form. The cry...
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ftpubmed:oai:pubmedcentral.nih.gov:2952259 2023-05-15T13:50:27+02:00 An Order-Disorder Transition Plays a Role in Switching Off the Root Effect in Fish Hemoglobins* Vergara, Alessandro Vitagliano, Luigi Merlino, Antonello Sica, Filomena Marino, Katia Verde, Cinzia di Prisco, Guido Mazzarella, Lelio 2010-10-15 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2952259 http://www.ncbi.nlm.nih.gov/pubmed/20610398 https://doi.org/10.1074/jbc.M110.143537 en eng American Society for Biochemistry and Molecular Biology http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2952259 http://www.ncbi.nlm.nih.gov/pubmed/20610398 http://dx.doi.org/10.1074/jbc.M110.143537 © 2010 by The American Society for Biochemistry and Molecular Biology, Inc. Protein Structure and Folding Text 2010 ftpubmed https://doi.org/10.1074/jbc.M110.143537 2013-09-03T05:40:06Z The Root effect is a widespread property among fish hemoglobins whose structural basis remains largely obscure. Here we report a crystallographic and spectroscopic characterization of the non-Root-effect hemoglobin isolated from the Antarctic fish Trematomus newnesi in the deoxygenated form. The crystal structure unveils that the T state of this hemoglobin is stabilized by a strong H-bond between the side chains of Asp95α and Asp101β at the α1β2 and α2β1 interfaces. This unexpected finding undermines the accepted paradigm that correlates the presence of this unusual H-bond with the occurrence of the Root effect. Surprisingly, the T state is characterized by an atypical flexibility of two α chains within the tetramer. Indeed, regions such as the CDα corner and the EFα pocket, which are normally well ordered in the T state of tetrameric hemoglobins, display high B-factors and non-continuous electron densities. This flexibility also leads to unusual distances between the heme iron and the proximal and distal His residues. These observations are in line with Raman micro-spectroscopy studies carried out both in solution and in the crystal state. The findings here presented suggest that in fish hemoglobins the Root effect may be switched off through a significant destabilization of the T state regardless of the presence of the inter-aspartic H-bond. Similar mechanisms may also operate for other non-Root effect hemoglobins. The implications of the flexibility of the CDα corner for the mechanism of the T-R transition in tetrameric hemoglobins are also discussed. Text Antarc* Antarctic PubMed Central (PMC) Antarctic The Antarctic Journal of Biological Chemistry 285 42 32568 32575 |
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English |
topic |
Protein Structure and Folding |
spellingShingle |
Protein Structure and Folding Vergara, Alessandro Vitagliano, Luigi Merlino, Antonello Sica, Filomena Marino, Katia Verde, Cinzia di Prisco, Guido Mazzarella, Lelio An Order-Disorder Transition Plays a Role in Switching Off the Root Effect in Fish Hemoglobins* |
topic_facet |
Protein Structure and Folding |
description |
The Root effect is a widespread property among fish hemoglobins whose structural basis remains largely obscure. Here we report a crystallographic and spectroscopic characterization of the non-Root-effect hemoglobin isolated from the Antarctic fish Trematomus newnesi in the deoxygenated form. The crystal structure unveils that the T state of this hemoglobin is stabilized by a strong H-bond between the side chains of Asp95α and Asp101β at the α1β2 and α2β1 interfaces. This unexpected finding undermines the accepted paradigm that correlates the presence of this unusual H-bond with the occurrence of the Root effect. Surprisingly, the T state is characterized by an atypical flexibility of two α chains within the tetramer. Indeed, regions such as the CDα corner and the EFα pocket, which are normally well ordered in the T state of tetrameric hemoglobins, display high B-factors and non-continuous electron densities. This flexibility also leads to unusual distances between the heme iron and the proximal and distal His residues. These observations are in line with Raman micro-spectroscopy studies carried out both in solution and in the crystal state. The findings here presented suggest that in fish hemoglobins the Root effect may be switched off through a significant destabilization of the T state regardless of the presence of the inter-aspartic H-bond. Similar mechanisms may also operate for other non-Root effect hemoglobins. The implications of the flexibility of the CDα corner for the mechanism of the T-R transition in tetrameric hemoglobins are also discussed. |
format |
Text |
author |
Vergara, Alessandro Vitagliano, Luigi Merlino, Antonello Sica, Filomena Marino, Katia Verde, Cinzia di Prisco, Guido Mazzarella, Lelio |
author_facet |
Vergara, Alessandro Vitagliano, Luigi Merlino, Antonello Sica, Filomena Marino, Katia Verde, Cinzia di Prisco, Guido Mazzarella, Lelio |
author_sort |
Vergara, Alessandro |
title |
An Order-Disorder Transition Plays a Role in Switching Off the Root Effect in Fish Hemoglobins* |
title_short |
An Order-Disorder Transition Plays a Role in Switching Off the Root Effect in Fish Hemoglobins* |
title_full |
An Order-Disorder Transition Plays a Role in Switching Off the Root Effect in Fish Hemoglobins* |
title_fullStr |
An Order-Disorder Transition Plays a Role in Switching Off the Root Effect in Fish Hemoglobins* |
title_full_unstemmed |
An Order-Disorder Transition Plays a Role in Switching Off the Root Effect in Fish Hemoglobins* |
title_sort |
order-disorder transition plays a role in switching off the root effect in fish hemoglobins* |
publisher |
American Society for Biochemistry and Molecular Biology |
publishDate |
2010 |
url |
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2952259 http://www.ncbi.nlm.nih.gov/pubmed/20610398 https://doi.org/10.1074/jbc.M110.143537 |
geographic |
Antarctic The Antarctic |
geographic_facet |
Antarctic The Antarctic |
genre |
Antarc* Antarctic |
genre_facet |
Antarc* Antarctic |
op_relation |
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2952259 http://www.ncbi.nlm.nih.gov/pubmed/20610398 http://dx.doi.org/10.1074/jbc.M110.143537 |
op_rights |
© 2010 by The American Society for Biochemistry and Molecular Biology, Inc. |
op_doi |
https://doi.org/10.1074/jbc.M110.143537 |
container_title |
Journal of Biological Chemistry |
container_volume |
285 |
container_issue |
42 |
container_start_page |
32568 |
op_container_end_page |
32575 |
_version_ |
1766253504062554112 |