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Title
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GLB-3 : a resilient, cysteine-rich, membrane-tethered globin expressed in the reproductive and nervous system of Caenorhabditis elegans
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Author
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Abstract
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| The popular genetic model organism Caenorhabditis elegans (C. elegans) encodes 34 globins, whereby the few that are well-characterized show divergent properties besides the typical oxygen carrier function. Here, we present a biophysical characterization and expression analysis of C. elegans globin-3 (GLB-3). GLB-3 is predicted to exist in two isoforms and is expressed in the reproductive and nervous system. Knockout of this globin causes a 99% reduction in fertility and reduced motility. Spectroscopic analysis reveals that GLB-3 exists as a bis-histidyl-ligated low-spin form in both the ferrous and ferric heme form. A function in binding of diatomic gases is excluded on the basis of the slow CO-binding kinetics. Unlike other globins, GLB-3 is also not capable of reacting with H2O2, H2S, and nitrite. Intriguingly, not only does GLB-3 contain a high number of cysteine residues, it is also highly stable under harsh conditions (pH = 2 and high concentrations of H2O2). The resilience diminishes when the N-and C-terminal extensions are removed. Redox potentiometric measurements reveal a slightly positive redox potential (+8 +/- 19 mV vs. SHE), suggesting that the heme iron may be able to oxidize cysteines. Electron paramagnetic resonance shows that formation of an intramolecular disulphide bridge, involving Cys70, affects the heme-pocket region. The results suggest an involvement of the globin in (cysteine) redox chemistry. |
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Language
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English
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Source (journal)
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Journal of inorganic biochemistry. - New York, N.Y.
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Publication
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New York, N.Y.
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2023
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ISSN
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0162-0134
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DOI
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10.1016/J.JINORGBIO.2022.112063
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Volume/pages
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238
(2023)
, p. 1-17
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Article Reference
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112063
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ISI
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000895763600004
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Pubmed ID
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36370505
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Medium
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E-only publicatie
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Full text (Publisher's DOI)
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Full text (open access)
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Full text (publisher's version - intranet only)
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