Structure of an unusual haemoprotein involved in thiosulfate oxidation

Bamford, Vicki A.; Rasmussen, Tim; Appia-Ayme, Corinne; Little, Phillip J.; Cheesman, Myles R.; Hemmings, Andrew M.; Berks, Ben C.

doi:10.1042/bst030a050b

Cited by 6 publications

(13 citation statements)

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“…2,10, 13 The reaction liberates two electrons that are passed on to an external electron acceptor which can be a cytochrome c 550 protein. 6 Sox complex-mediated sulfur oxidation pathways have been found in bacteria isolated from both neutral and alkaline pH environments 14, 15 , but not in acidophilic bacteria.…”

Section: B I O L O G I C a L F U N C T I O Nmentioning

confidence: 99%

“…9, 13 A His/Met-ligated heme group is found in all SoxX subunits while SoxA subunits contain either one or two His/Cys-ligated heme groups. In Type I SoxAX proteins, only the SoxA heme group that is located close to the proposed active site at the SoxAX subunit interface is thought to be catalytically active.…”

Section: E Ta L C O N T E N T a N D C O Fa C T O R Smentioning

confidence: 99%

“…The heme 2 binding sites in all three crystal structures are proposed to be the active sites, due in part to the observation of posttranslational modification to one of the coordinating ligands. 13 In the RsSoxAX and PpSoxAX structures, the heme 2 cofactor is coordinated by a histidine and a cysteine ligand that is quantitatively modified to a cysteine persulfide (CysS − ). In the SnSoxAX structure, however, an equal mixture of Cys and posttranslationally modified CysS − were observed in this position ( Figure 3).…”

Section: Heme-binding Site Structuresmentioning

confidence: 99%

“…The CysS − modification has been suggested to result from incomplete catalysis, where only the thiosulfate sulfone sulfur (rather than the entire thiosulfate moiety) is transferred to the SoxYZ protein. 13 The heme 3 cofactor is coordinated by the SoxX subunit with axial ligands His and Met. In all three structures, the heme cofactor and propionate groups form part of the solvent-exposed surface of the protein (Figure 3).…”

Section: Heme-binding Site Structuresmentioning

confidence: 99%

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SoxAXCytochromes

Kappler

Maher

2004

Encyclopedia of Inorganic and Bioinorganic Chemistry

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SoxAX cytochromes catalyze the formation of a disulfide bond between a reduced inorganic sulfur substrate and a conserved cysteine residue present on the SoxYZ carrier protein. The reaction liberates two electrons that are transferred to an external electron acceptor, usually a small c ‐type cytochrome. SoxAX cytochromes are essential components of the bacterial sulfur oxidation (Sox) pathway that is found in both chemo‐ and phototrophic bacteria, and currently there are three known structurally distinct types of SoxAX cytochromes that may represent adaptations of this enzyme to specific metabolic functions. Crystal structures are available for two of the three types of SoxAX proteins and revealed that one of the two active site hemes has a His/Cys‐persulfide ligand environment. This specific ligand field gives rise to extremely negative redox potentials, and in addition to several heme groups SoxAX cytochromes may contain a Cu redox center. Evidence from electron paramagnetic resonance (EPR) and magnetic circular dichroism (MCD) spectroscopy indicates a high flexibility of the SoxAX active site heme environment and suggests that the reaction mechanism may involve a ligand exchange reaction.

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Section: B I O L O G I C a L F U N C T I O Nmentioning

confidence: 99%

Section: E Ta L C O N T E N T a N D C O Fa C T O R Smentioning

confidence: 99%

Section: Heme-binding Site Structuresmentioning

confidence: 99%

Section: Heme-binding Site Structuresmentioning

confidence: 99%

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SoxAXCytochromes

Kappler

Maher

2004

Encyclopedia of Inorganic and Bioinorganic Chemistry

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“…Four periplasmic proteins, SoxYZ, SoxB, SoxCD and SoxXA, reconstitute the Sox enzyme system in vitro, which oxidizes hydrogen sulfide, sulfur, thiosulfate and sulfite, and transfers the electrons to horse cytochrome c. The heterodimeric haem enzyme SoxXA binds the sulfur substrate and covalently links it to the thiol of the single cysteine110 residue of the SoxY subunit (10 977 Da) (Bamford et al, 2002). With SoxZ (11 719 Da), SoxY forms the metal-and cofactorless SoxYZ complex.…”

Section: Introductionmentioning

confidence: 99%

Sulfur oxidation of Paracoccus pantotrophus: the sulfur-binding protein SoxYZ is the target of the periplasmic thiol-disulfide oxidoreductase SoxS

2008

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Synthesis, Isolation, and Characterization of a Phenylsulfane-Selenolate Compound

Jungen

Chen

2020

Inorg. Chem.

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The first example of a stable phenylsulfaneselenoate species was synthesized in a one-step process and isolated as the tetraphenylphosphonium salt [PPh4][PhSSe] as indicated by X-ray crystal structure analysis. Electrospray ionization mass spectrometry and NMR studies in solution showed the compound to enter a complex system of equilibria when dissolved. Computations suggested a high barrier for rotation around the C-S bond, indicating a π-system conjugated over the whole molecule. In general, the compound is closely related to the recently isolated [PPh4][PhS2] perthiolate salt.

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Structure of an unusual haemoprotein involved in thiosulfate oxidation

Cited by 6 publications

References 0 publications

SoxAXCytochromes

SoxAXCytochromes

Sulfur oxidation of Paracoccus pantotrophus: the sulfur-binding protein SoxYZ is the target of the periplasmic thiol-disulfide oxidoreductase SoxS

Synthesis, Isolation, and Characterization of a Phenylsulfane-Selenolate Compound

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