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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Online Access: | https://doi.org/10.1074/jbc.M110.143537 https://pubmed.ncbi.nlm.nih.gov/20610398 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2952259/ |
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ftpubmed:20610398 2024-06-09T07:41:09+00:00 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 Oct 15 https://doi.org/10.1074/jbc.M110.143537 https://pubmed.ncbi.nlm.nih.gov/20610398 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2952259/ eng eng Elsevier Science https://doi.org/10.1074/jbc.M110.143537 https://pubmed.ncbi.nlm.nih.gov/20610398 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2952259/ J Biol Chem ISSN:1083-351X Volume:285 Issue:42 Journal Article Research Support, Non-U.S. Gov't 2010 ftpubmed https://doi.org/10.1074/jbc.M110.143537 2024-05-11T16:02:00Z 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 α(1)β(2) and α(2)β(1) 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. Article in Journal/Newspaper Antarc* Antarctic PubMed Central (PMC) Antarctic The Antarctic Journal of Biological Chemistry 285 42 32568 32575 |
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PubMed Central (PMC) |
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ftpubmed |
language |
English |
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 α(1)β(2) and α(2)β(1) 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 |
Article in Journal/Newspaper |
author |
Vergara, Alessandro Vitagliano, Luigi Merlino, Antonello Sica, Filomena Marino, Katia Verde, Cinzia di Prisco, Guido Mazzarella, Lelio |
spellingShingle |
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. |
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 |
Elsevier Science |
publishDate |
2010 |
url |
https://doi.org/10.1074/jbc.M110.143537 https://pubmed.ncbi.nlm.nih.gov/20610398 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2952259/ |
geographic |
Antarctic The Antarctic |
geographic_facet |
Antarctic The Antarctic |
genre |
Antarc* Antarctic |
genre_facet |
Antarc* Antarctic |
op_source |
J Biol Chem ISSN:1083-351X Volume:285 Issue:42 |
op_relation |
https://doi.org/10.1074/jbc.M110.143537 https://pubmed.ncbi.nlm.nih.gov/20610398 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2952259/ |
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_ |
1801369595328593920 |