Biophysical Characterisation of Neuroglobin of the Icefish, a Natural Knockout for Hemoglobin and Myoglobin. Comparison with Human Neuroglobin

The Antarctic icefish Chaenocephalus aceratus lacks the globins common to most vertebrates, hemoglobin and myoglobin, but has retained neuroglobin in the brain. This conserved globin has been cloned, over-expressed and purified. To highlight similarities and differences, the structural features of t...

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Bibliographic Details
Published in:PLoS ONE
Main Authors: Giordano, Daniela, Boron, Ignacio, Abbruzzetti, Stefania, Van Leuven, Wendy, Nicoletti, Francesco P., Forti, Flavio, Bruno, Stefano, Cheng, C-H. Christina, Moens, Luc, di Prisco, Guido, Nadra, Alejandro D., Estrin, Darío, Smulevich, Giulietta, Dewilde, Sylvia, Viappiani, Cristiano, Verde, Cinzia
Format: Text
Language:English
Published: Public Library of Science 2012
Subjects:
Research Article
Antarctic
The Antarctic
Antarc*
Icefish
Online Access:http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3513292
http://www.ncbi.nlm.nih.gov/pubmed/23226490
https://doi.org/10.1371/journal.pone.0044508
Description
Summary:The Antarctic icefish Chaenocephalus aceratus lacks the globins common to most vertebrates, hemoglobin and myoglobin, but has retained neuroglobin in the brain. This conserved globin has been cloned, over-expressed and purified. To highlight similarities and differences, the structural features of the neuroglobin of this colourless-blooded fish were compared with those of the well characterised human neuroglobin as well as with the neuroglobin from the retina of the red blooded, hemoglobin and myoglobin-containing, closely related Antarctic notothenioid Dissostichus mawsoni. A detailed structural and functional analysis of the two Antarctic fish neuroglobins was carried out by UV-visible and Resonance Raman spectroscopies, molecular dynamics simulations and laser-flash photolysis. Similar to the human protein, Antarctic fish neuroglobins can reversibly bind oxygen and CO in the Fe2+ form, and show six-coordination by distal His in the absence of exogenous ligands. A very large and structured internal cavity, with discrete docking sites, was identified in the modelled three-dimensional structures of the Antarctic neuroglobins. Estimate of the free-energy barriers from laser-flash photolysis and Implicit Ligand Sampling showed that the cavities are accessible from the solvent in both proteins.

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