Theoretical study of the mechanism of the manganese catalase KatB

Yang, Xiaodong; Mao, Qiuyun; An, Xiao-Ting; Li, Xichen; Siegbahn, Per E. M.; Chen, Guangju; Tan, Hongwei

doi:10.1007/s00775-018-1631-z

Cited by 5 publications

(2 citation statements)

References 29 publications

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“…The other component with antiferromagnetic coupling is similar in energy, showing that the coupling is weak. As shown in Figure a, the O–O distance in (OH lig ···OH free ) •– is as short as 2.20 Å, resembling the immediate O–O bond cleavage intermediate in H 2 O 2 disproportionation catalyzed by manganese catalases. , Two second-sphere water molecules, together with the unprotonated oxyanion groups on the bipyridine, form an extensive hydrogen-bonding network that stabilizes the (OH lig ···OH free ) •– moiety. As shown in the figure, there is a significant distribution of up-spin population within the (OH lig ···OH free ) •– moiety.…”

Section: Resultsmentioning

confidence: 93%

Theoretical Study of the Mechanisms of Two Copper Water Oxidation Electrocatalysts with Bipyridine Ligands

Mao

Pang

et al. 2019

ACS Catal.

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Hybrid density functional theory was employed to study the reaction mechanisms of two homogeneous copper water oxidation catalysts (WOCs), [(L22–)CuII(OH2)2] (H2L2 = 6,6′-dihydroxy-2,2′-bipyridine) [turnover frequency (TOF) = 0.4 s–1 at an overpotential = 640 mV and pH 12.4] and [(L1)CuII(OH–)2] (L1 = 2,2′-bipyridine) (TOF = 100 s–1 at an overpotential = 850 mV and pH 12.5). Interesting mechanistic insights were obtained by systematically exploring different oxidation and protonation states along reaction pathways. Two well-established protocols to compute the thermodynamics of proton and electron release processes were employed, and similar results were obtained. For the [(L22–)CuII(OH2)2] WOC, two distinct types of water oxidation mechanisms were found with similar rate-limiting barriers, cosubstrate and hydroxyl coupling, termed as such because of the characteristics of the O–O bond formation transition states. For the cosubstrate mechanism, after the starting species is oxidized twice, an O–O bond is formed between the copper-bound terminal oxyl radical ligand and its adjacent oxyanion substituent on the bipyridine radicaloid, showing an interesting mechanistic role for the electron-donating proton-responsive hydroxyl substituent. After the third oxidation of the complex, the organic peroxyl moiety is displaced into an inorganic superoxide by a free anionic hydroxide, which is the rate-limiting step in the cosubstrate mechanism. For the hydroxyl coupling mechanism, after two oxidations of the starting species, O–O bond formation occurs through coupling within the copper-bound (OHlig···OHfree)•– moiety, with hydrogen-bonding stabilization from the 6,6′-oxyanions and the ligating and free water molecules. For the parent [(L1)CuII(OH–)2] WOC, O–O bond formation was suggested to occur through coupling between the copper-bound oxyl radical and hydroxide ligands. The results could be useful for further improvement of Cu WOCs.

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Section: Resultsmentioning

confidence: 93%

Theoretical Study of the Mechanisms of Two Copper Water Oxidation Electrocatalysts with Bipyridine Ligands

Mao

Pang

et al. 2019

ACS Catal.

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“…In organisms, Mn 2+ plays a crucial role in the activity of CAT and promotes the production of H 2 O and O 2 . [39] Surprisingly, the excellent CAT activity of Mn(20%)-ZIF-8 nanocomposites was at least twice as high as those of the widely reported nanozymes including CeO 2 , MnO 2 and Mn 3 O 4 . [22,23,25] In terms of SOD activity, the enzyme activity of the R-Mn(20%)-ZIF-8 nanocomposites increased significantly due to the increase of the concentration of Mn 2+ , which can provide a low valence state for the SOD enzyme activity to directly scavenge free radicals.…”

Section: Characterization Of Mn-zif-8 Nanocompositesmentioning

confidence: 86%

Antibacterial Zeolite Imidazole Frameworks with Manganese Doping for Immunomodulation to Accelerate Infected Wound Healing

Wan

Jiao

Wang

et al. 2021

Adv Healthcare Materials

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Numerous nanomedicines currently emerge to reduce the dramatic threat in antibiotics resistance for antibacterial application against severe bacterial infections, while it is restricted by over-reacted immune response to pathogenic bacteria. Herein, enzymatic activity is introduced into the zeolitic imidazolate framework-8 (ZIF-8) to achieve sterilization by releasing Zn ions, as well as inflammation regulation through the variable valence of Mn ions that are uniformly doped into its framework. Within this simple metal organic framework (MOF) structure design, Mn-ZIF-8 possesses the co-existence of Mn 2+ /Mn 4+ to endow the nanocomposite with the anti-inflammatory capabilities, which can be adjusted through the redox environment. The enzymatic activity of Mn ions and superiority of pore structure of ZIF-8 are effectively combined to realize the substrate selection via reactant molecular size and high-efficiency internal catalytic performance. By such design, this nanocomposite would not only exhibit an excellent antibacterial performance against pathogenic bacteria, but also reshape the inflammatory immunity by regulating macrophage polarization to suppress over-reacted inflammation, leading to a favorably therapeutic efficiency on bacteria-infected wound healing in animal models. Taken together, this nanoplatform provides effective approach for accelerating infected wound healing via bacteria killing and inflammation modulation, and may be extended for the therapy of other severe bacteria-induced infections.

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Gut microbial metalloproteins and its role in xenobiotics degradation and ROS scavenging

Mohite,

Sharma

2024

Advances in Protein Chemistry and Structural Biology

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Theoretical study of the mechanism of the manganese catalase KatB

Cited by 5 publications

References 29 publications

Theoretical Study of the Mechanisms of Two Copper Water Oxidation Electrocatalysts with Bipyridine Ligands

Theoretical Study of the Mechanisms of Two Copper Water Oxidation Electrocatalysts with Bipyridine Ligands

Antibacterial Zeolite Imidazole Frameworks with Manganese Doping for Immunomodulation to Accelerate Infected Wound Healing

Gut microbial metalloproteins and its role in xenobiotics degradation and ROS scavenging

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