TY - JOUR
T1 - Antarctic fish versus human cytoglobins – The same but yet so different
AU - Cuypers, Bert
AU - Vermeylen, Stijn
AU - Hammerschmid, Dietmar
AU - Trashin, Stanislav
AU - Rahemi, Vanoushe
AU - Konijnenberg, Albert
AU - De Schutter, Amy
AU - Cheng, C. H.Christina
AU - Giordano, Daniela
AU - Verde, Cinzia
AU - De Wael, Karolien
AU - Sobott, Frank
AU - Dewilde, Sylvia
AU - Van Doorslaer, Sabine
N1 - Publisher Copyright:
© 2017 Elsevier Inc.
PY - 2017/8/1
Y1 - 2017/8/1
N2 - The cytoglobins of the Antarctic fish Chaenocephalus aceratus and Dissostichus mawsoni have many features in common with human cytoglobin. These cytoglobins are heme proteins in which the ferric and ferrous forms have a characteristic hexacoordination of the heme iron, i.e. axial ligation of two endogenous histidine residues, as confirmed by electron paramagnetic resonance, resonance Raman and optical absorption spectroscopy. The combined spectroscopic analysis revealed only small variations in the heme-pocket structure, in line with the small variations observed for the redox potential. Nevertheless, some striking differences were also discovered. Resonance Raman spectroscopy showed that the stabilization of an exogenous heme ligand, such as CO, occurs differently in human cytoglobin in comparison with Antarctic fish cytoglobins. Furthermore, while it has been extensively reported that human cytoglobin is essentially monomeric and can form an intramolecular disulfide bridge that can influence the ligand binding kinetics, 3D modeling of the Antarctic fish cytoglobins indicates that the cysteine residues are too far apart to form such an intramolecular bridge. Moreover, gel filtration and mass spectrometry reveal the occurrence of non-covalent multimers (up to pentamers) in the Antarctic fish cytoglobins that are formed at low concentrations. Stabilization of these oligomers by disulfide-bridge formation is possible, but not essential. If intermolecular disulfide bridges are formed, they influence the heme-pocket structure, as is shown by EPR measurements.
AB - The cytoglobins of the Antarctic fish Chaenocephalus aceratus and Dissostichus mawsoni have many features in common with human cytoglobin. These cytoglobins are heme proteins in which the ferric and ferrous forms have a characteristic hexacoordination of the heme iron, i.e. axial ligation of two endogenous histidine residues, as confirmed by electron paramagnetic resonance, resonance Raman and optical absorption spectroscopy. The combined spectroscopic analysis revealed only small variations in the heme-pocket structure, in line with the small variations observed for the redox potential. Nevertheless, some striking differences were also discovered. Resonance Raman spectroscopy showed that the stabilization of an exogenous heme ligand, such as CO, occurs differently in human cytoglobin in comparison with Antarctic fish cytoglobins. Furthermore, while it has been extensively reported that human cytoglobin is essentially monomeric and can form an intramolecular disulfide bridge that can influence the ligand binding kinetics, 3D modeling of the Antarctic fish cytoglobins indicates that the cysteine residues are too far apart to form such an intramolecular bridge. Moreover, gel filtration and mass spectrometry reveal the occurrence of non-covalent multimers (up to pentamers) in the Antarctic fish cytoglobins that are formed at low concentrations. Stabilization of these oligomers by disulfide-bridge formation is possible, but not essential. If intermolecular disulfide bridges are formed, they influence the heme-pocket structure, as is shown by EPR measurements.
KW - Cytoglobin
KW - Electron paramagnetic resonance
KW - Mass spectrometry
KW - Protein expression
KW - Redox
KW - Resonance Raman spectroscopy
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U2 - 10.1016/j.jinorgbio.2017.04.025
DO - 10.1016/j.jinorgbio.2017.04.025
M3 - Article
C2 - 28501743
AN - SCOPUS:85019074558
SN - 0162-0134
VL - 173
SP - 66
EP - 78
JO - Journal of Inorganic Biochemistry
JF - Journal of Inorganic Biochemistry
ER -