Theoretical Model of the Structure and the Reaction Mechanisms of Sulfur Oxygenase Reductase in Acidithiobacillus thiooxidans

2015 ◽  
Vol 1130 ◽  
pp. 67-70 ◽  
Author(s):  
Xian Zhang ◽  
Hua Qun Yin ◽  
Yi Li Liang ◽  
Guan Zhou Qiu ◽  
Xue Duan Liu
Keyword(s):  
Draft Genome ◽  
Sulfur Oxidation ◽  
Heme Iron ◽  
Acidithiobacillus Thiooxidans ◽  
Non Heme Iron ◽  
Substrate Activation ◽  
Reductase Gene ◽  
Dna Fragment ◽  
Important Enzyme ◽  
Sulfur Oxygenase Reductase

Sulfur oxygenase reductase (SOR), which is thought to be an important enzyme involved in sulfur oxidation in many microorganisms, may play a key role in sulfur oxidation in Acidithiobacillusthiooxidans. Draft genome sequence of A. thiooxidans A01 indicated the presence of sulfur oxygenase reductase gene (sor). The complementary DNA fragment was speculated to encode a putative 311-aa full-length protein SOR. Structural analysis of SOR revealed that three cysteines located in the two conserved domains, C32 at V-G-P-K-V-C32 as well as C102 and C105 at C102-X-X-C105, might form the substrate activation and binding site. It was proposed that conserved motif H87-X3-H91-X23-E115 acted as ligands might combine with iron atom to constitute a mononuclear non-heme iron center, catalyzing the oxidation reaction of substrate.

scholarly journals Novel Three-Component Rieske Non-Heme Iron Oxygenase System Catalyzing theN-Dealkylation of Chloroacetanilide Herbicides in Sphingomonads DC-6 and DC-2

2014 ◽  
Vol 80 (16) ◽  
pp. 5078-5085 ◽  
Author(s):  
Qing Chen ◽  
Cheng-Hong Wang ◽  
Shi-Kai Deng ◽  
Ya-Dong Wu ◽  
Yi Li ◽  
...  
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequence ◽  
Heme Iron ◽  
Content Type ◽  
Non Heme Iron ◽  
Transport Component ◽  
Reductase Gene ◽  
Chloroacetanilide Herbicides ◽  
The Individual ◽  
Sequence Identities

ABSTRACTSphingomonads DC-6 and DC-2 degrade the chloroacetanilide herbicides alachlor, acetochlor, and butachlor viaN-dealkylation. In this study, we report a three-component Rieske non-heme iron oxygenase (RHO) system catalyzing theN-dealkylation of these herbicides. The oxygenase component genecndAis located in a transposable element that is highly conserved in the two strains. CndA shares 24 to 42% amino acid sequence identities with the oxygenase components of some RHOs that catalyzeN- orO-demethylation. Two putative [2Fe-2S] ferredoxin genes and one glutathione reductase (GR)-type reductase gene were retrieved from the genome of each strain. These genes were not located in the immediate vicinity ofcndA. The four ferredoxins share 64 to 72% amino acid sequence identities to the ferredoxin component of dicambaO-demethylase (DMO), and the two reductases share 62 to 65% amino acid sequence identities to the reductase component of DMO.cndA, the four ferredoxin genes, and the two reductases genes were expressed inEscherichia coli, and the recombinant proteins were purified using Ni-affinity chromatography. The individual components or the components in pairs displayed no activity; the enzyme mixture showedN-dealkylase activities toward alachlor, acetochlor, and butachlor only when CndA-His6was combined with one of the four ferredoxins and one of the two reductases, suggesting that the enzyme consists of three components, a homo-oligomer oxygenase, a [2Fe-2S] ferredoxin, and a GR-type reductase, and CndA has a low specificity for the electron transport component (ETC). TheN-dealkylase utilizes NADH, but not NADPH, as the electron donor.

The archaeal non-heme iron-containing Sulfur Oxygenase Reductase

2022 ◽  
Vol 455 ◽  
pp. 214358
Author(s):  
P. Ferreira ◽  
P.A. Fernandes ◽  
M.J. Ramos
Keyword(s):  
Heme Iron ◽  
Non Heme Iron ◽  
Sulfur Oxygenase Reductase

Strongly Coupled Redox-Linked Conformational Switching at the Active Site of the Non-Heme Iron-Dependent Dioxygenase, TauD

2019 ◽  
Author(s):  
Christopher John ◽  
Greg M. Swain ◽  
Robert P. Hausinger ◽  
Denis A. Proshlyakov
Keyword(s):  
Active Site ◽  
Structural Model ◽  
Heme Iron ◽  
Chemical Transformations ◽  
Experimental Conditions ◽  
Strongly Coupled ◽  
Non Heme Iron ◽  
Reversible Redox ◽  
Wide Range ◽  
Complex Structural

2-Oxoglutarate (2OG)-dependent dioxygenases catalyze C-H activation while performing a wide range of chemical transformations. In contrast to their heme analogues, non-heme iron centers afford greater structural flexibility with important implications for their diverse catalytic mechanisms. We characterize an <i>in situ</i> structural model of the putative transient ferric intermediate of 2OG:taurine dioxygenase (TauD) by using a combination of spectroelectrochemical and semi-empirical computational methods, demonstrating that the Fe (III/II) transition involves a substantial, fully reversible, redox-linked conformational change at the active site. This rearrangement alters the apparent redox potential of the active site between -127 mV for reduction of the ferric state and 171 mV for oxidation of the ferrous state of the 2OG-Fe-TauD complex. Structural perturbations exhibit limited sensitivity to mediator concentrations and potential pulse duration. Similar changes were observed in the Fe-TauD and taurine-2OG-Fe-TauD complexes, thus attributing the reorganization to the protein moiety rather than the cosubstrates. Redox difference infrared spectra indicate a reorganization of the protein backbone in addition to the involvement of carboxylate and histidine ligands. Quantitative modeling of the transient redox response using two alternative reaction schemes across a variety of experimental conditions strongly supports the proposal for intrinsic protein reorganization as the origin of the experimental observations.

Plant carotenoid cleavage oxygenases: structure–function relationships and role in development and metabolism

2019 ◽  
Vol 19 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Manoj Kumar Dhar ◽  
Sonal Mishra ◽  
Archana Bhat ◽  
Sudha Chib ◽  
Sanjana Kaul
Keyword(s):  
Higher Plants ◽  
Domain Architecture ◽  
Heme Iron ◽  
Critical Assessment ◽  
Protein Family ◽  
Regulatory Mechanisms ◽  
Non Heme Iron ◽  
Functional Aspects ◽  
Functional Understanding ◽  
Signal Production

Abstract A plant communicates within itself and with the outside world by deploying an array of agents that include several attractants by virtue of their color and smell. In this category, the contribution of ‘carotenoids and apocarotenoids’ is very significant. Apocarotenoids, the carotenoid-derived compounds, show wide representation among organisms. Their biosynthesis occurs by oxidative cleavage of carotenoids, a high-value reaction, mediated by carotenoid cleavage oxygenases or carotenoid cleavage dioxygenases (CCDs)—a family of non-heme iron enzymes. Structurally, this protein family displays wide diversity but is limited in its distribution among plants. Functionally, this protein family has been recognized to offer a role in phytohormones, volatiles and signal production. Further, their wide presence and clade-specific functional disparity demands a comprehensive account. This review focuses on the critical assessment of CCDs of higher plants, describing recent progress in their functional aspects and regulatory mechanisms, domain architecture, classification and localization. The work also highlights the relevant discussion for further exploration of this multi-prospective protein family for the betterment of its functional understanding and improvement of crops.

scholarly journals Activation modes in biocatalytic radical cyclization reactions

2021 ◽  
Author(s):  
Yuxuan Ye ◽  
Haigen Fu ◽  
Todd K Hyster
Keyword(s):  
Heme Iron ◽  
Radical Cyclization ◽  
Cytochrome P450 Monooxygenases ◽  
Radical Cyclizations ◽  
Cyclization Reactions ◽  
Complex Molecules ◽  
P450 Monooxygenases ◽  
Non Heme Iron ◽  
Essential Reactions ◽  
Isopenicillin N

Abstract Radical cyclizations are essential reactions in the biosynthesis of secondary metabolites and the chemical synthesis of societally valuable molecules. In this review, we highlight the general mechanisms utilized in biocatalytic radical cyclizations. We specifically highlight cytochrome P450 monooxygenases (P450s) involved in the biosynthesis of mycocyclosin and vancomycin, non-heme iron- and α-ketoglutarate-dependent dioxygenases (Fe/αKGDs) used in the biosynthesis of kainic acid, scopolamine, and isopenicillin N, and radical S-adenosylmethionine (SAM) enzymes that facilitate the biosynthesis of oxetanocin A, menaquinone, and F420. Beyond natural mechanisms, we also examine repurposed flavin-dependent ‘ene’-reductases (ERED) for non-natural radical cyclization. Overall, these general mechanisms underscore the opportunity for enzymes to augment and enhance the synthesis of complex molecules using radical mechanisms.

scholarly journals Non-heme Iron Proteins

1968 ◽  
Vol 243 (23) ◽  
pp. 6262-6272 ◽  
Author(s):  
J N Tsunoda ◽  
K T Yasunobu ◽  
H R Whiteley
Keyword(s):  
Heme Iron ◽  
Iron Proteins ◽  
Non Heme Iron
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