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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ftunivnapoliiris:oai:www.iris.unina.it:11588/371043 2024-04-14T08:02:56+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 MAZZARELLA, LELIO K. Marino C. Verde G. di Prisco Vergara, Alessandro Vitagliano, Luigi Merlino, Antonello Sica, Filomena K., Marino C., Verde G., di Prisco Mazzarella, Lelio 2010 STAMPA http://hdl.handle.net/11588/371043 https://doi.org/10.1074/jbc.M110.143537 http://www.jbc.org/content/285/42/32568.long eng eng info:eu-repo/semantics/altIdentifier/pmid/20610398 info:eu-repo/semantics/altIdentifier/wos/WOS:000282683000071 volume:285 issue:42 firstpage:32568 lastpage:32575 numberofpages:8 journal:THE JOURNAL OF BIOLOGICAL CHEMISTRY http://hdl.handle.net/11588/371043 doi:10.1074/jbc.M110.143537 info:eu-repo/semantics/altIdentifier/scopus/2-s2.0-77957778513 http://www.jbc.org/content/285/42/32568.long info:eu-repo/semantics/closedAccess info:eu-repo/semantics/article 2010 ftunivnapoliiris https://doi.org/10.1074/jbc.M110.143537 2024-03-21T19:03:20Z 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 IRIS Università degli Studi di Napoli Federico II Antarctic The Antarctic Journal of Biological Chemistry 285 42 32568 32575 |
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IRIS Università degli Studi di Napoli Federico II |
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ftunivnapoliiris |
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. |
author2 |
Vergara, Alessandro Vitagliano, Luigi Merlino, Antonello Sica, Filomena K., Marino C., Verde G., di Prisco Mazzarella, Lelio |
format |
Article in Journal/Newspaper |
author |
VERGARA, ALESSANDRO VITAGLIANO, LUIGI MERLINO, ANTONELLO SICA, FILOMENA MAZZARELLA, LELIO K. Marino C. Verde G. di Prisco |
spellingShingle |
VERGARA, ALESSANDRO VITAGLIANO, LUIGI MERLINO, ANTONELLO SICA, FILOMENA MAZZARELLA, LELIO K. Marino C. Verde G. di Prisco 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 MAZZARELLA, LELIO K. Marino C. Verde G. di Prisco |
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 |
publishDate |
2010 |
url |
http://hdl.handle.net/11588/371043 https://doi.org/10.1074/jbc.M110.143537 http://www.jbc.org/content/285/42/32568.long |
geographic |
Antarctic The Antarctic |
geographic_facet |
Antarctic The Antarctic |
genre |
Antarc* Antarctic |
genre_facet |
Antarc* Antarctic |
op_relation |
info:eu-repo/semantics/altIdentifier/pmid/20610398 info:eu-repo/semantics/altIdentifier/wos/WOS:000282683000071 volume:285 issue:42 firstpage:32568 lastpage:32575 numberofpages:8 journal:THE JOURNAL OF BIOLOGICAL CHEMISTRY http://hdl.handle.net/11588/371043 doi:10.1074/jbc.M110.143537 info:eu-repo/semantics/altIdentifier/scopus/2-s2.0-77957778513 http://www.jbc.org/content/285/42/32568.long |
op_rights |
info:eu-repo/semantics/closedAccess |
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 |
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1796318731768430592 |