The heme pocket of the globin domain of the globin-coupled sensor of Geobacter sulfurreducens — An EPR study

Desmet, Filip; Thijs, Liesbet; Mkami, Hassane El; Dewilde, Sylvia; Moëns, Luc; Smith, Graham; Doorslaer, Sabine Van

doi:10.1016/j.jinorgbio.2010.05.009

Cited by 8 publications

(5 citation statements)

References 37 publications

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“…As shown earlier, 1 H HYSCORE [40,68] and 1 H ENDOR [69] reveal the hyperfine interaction with the nearby His protons that reflect the distance and rotation of the His imidazole planes versus the g tensor frame. The 1 H ENDOR spectra of ferric C.aceCygb-1 and D.mawCygb-1 were found to be the same ( Supplementary Fig.…”

Section: Electron Paramagnetic Resonancesupporting

confidence: 57%

Antarctic fish versus human cytoglobins – The same but yet so different

Cuypers

Vermeylen

Hammerschmid

et al. 2017

Journal of Inorganic Biochemistry

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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.

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Section: Electron Paramagnetic Resonancesupporting

confidence: 57%

Antarctic fish versus human cytoglobins – The same but yet so different

Cuypers

Vermeylen

Hammerschmid

et al. 2017

Journal of Inorganic Biochemistry

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“…The | A zz | hyperfine values of heme 14 N nuclei are not only very different among each other, but even more interestingly, at least one has a hyperfine value as low as 3.9 MHz. If we compare this with known Fe(III) heme systems that are considered to have a “pure” (d xy ) 2 (d xz ,d yz ) 3 ground state, all reported | A zz | values of the heme nitrogens are in the order of 5.4–6.1 MHz (Table ). ,,,− This is found independent of the type of the axial ligands (His, Cys, imidazole, CN – ) and independent of the corresponding g z values, and hence the ligand-field parameters. In contrast, Astashkin et al observed hyperfine values for the pyrrole nitrogens of 3.3(±0.5) MHz for bis(phenyl isocyanide) complexes of iron(III) porphyrins exhibiting the (d xz ,d yz ) 4 (d xy ) 1 ground state.…”

Section: Discussionmentioning

confidence: 88%

Marked Difference in the Electronic Structure of Cyanide-Ligated Ferric Protoglobins and Myoglobin Due to Heme Ruffling

Doorslaer

Tilleman²,

Verrept³

et al. 2012

Inorg. Chem.

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Electron paramagnetic resonance experiments reveal a significant difference between the principal g values (and hence ligand-field parameters) of the ferric cyanide-ligated form of different variants of the protoglobin of Methanosarcina acetivorans (MaPgb) and of horse heart myoglobin (hhMb). The largest principal g value of the ferric cyanide-ligated MaPgb variants is found to be significantly lower than for any of the other globins reported so far. This is at least partially caused by the strong heme distortions as proven by the determination of the hyperfine interaction of the heme nitrogens and mesoprotons. Furthermore, the experiments confirm recent theoretical predictions [Forti, F.; Boechi, L., Bikiel, D., Martí, M.A.; Nardini, M.; Bolognesi, M.; Viappiani, C.; Estrin, D.; Luque, F. J. J. Phys. Chem. B 2011, 115, 13771-13780] that Phe(G8)145 plays a crucial role in the ligand modulation in MaPgb. Finally, the influence of the N-terminal 20 amino-acid chain on the heme pocket in these protoglobins is also proven.

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“…In addition, the distal pocket tyrosine (Y40) was found to be pointed away from the distal pocket, in contrast to structures of HemAT- Bs . Gs GCS was demonstrated to bind O 2 , NO, and CO, and exhibited monophasic O 2 dissociation kinetics, potentially due to the altered heme pocket (Desmet et al, 2010; Pesce et al, 2009). However, as yet the in vivo function of Gs GCS and the mechanism of activation require further study.…”

Section: Gcs Proteins Of Unknown Functionmentioning

confidence: 99%

Mechanism and Role of Globin-Coupled Sensor Signalling

Walker

Rivera

Weinert

2017

Advances in Microbial Physiology

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The discovery of the globin-coupled sensor (GCS) family of haem proteins has provided new insights into signalling proteins and pathways by which organisms sense and respond to changing oxygen levels. GCS proteins consist of a sensor globin domain linked to a variety of output domains, suggesting roles in controlling numerous cellular pathways, and behaviours in response to changing oxygen concentration. Members of this family of proteins have been identified in the genomes of numerous organisms and characterization of GCS with output domains, including methyl accepting chemotaxis proteins, kinases, and diguanylate cyclases, have yielded an understanding of the mechanism by which oxygen controls activity of GCS protein output domains, as well as downstream proteins and pathways regulated by GCS signalling. Future studies will expand our understanding of these proteins both in vitro and in vivo, likely demonstrating broad roles for GCS in controlling oxygen-dependent microbial physiology and phenotypes.

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The heme pocket of the globin domain of the globin-coupled sensor of Geobacter sulfurreducens — An EPR study

Cited by 8 publications

References 37 publications

Antarctic fish versus human cytoglobins – The same but yet so different

Antarctic fish versus human cytoglobins – The same but yet so different

Marked Difference in the Electronic Structure of Cyanide-Ligated Ferric Protoglobins and Myoglobin Due to Heme Ruffling

Mechanism and Role of Globin-Coupled Sensor Signalling

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