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pH-Dependence of manganese (II) Oxidation Reaction by Novel Wild-Type and Mutants Recombinant Phlebia radiata manganese peroxidase 3 (rPr-MnP3) Enzymes

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American Journal of Molecular Biology 2022年第2期12卷 67-84页

作者： Usenobong F. Ufot Monday I. Akpanabiatu Khasim Cali Ifiok D. Uffia Inyang Udosen Department of Genetics and Biotechnology Faculty of Biological Sciences Akwa Ibom State University Uyo Akwa Ibom State Nigeria Department of Biochemistry Faculty of Sciences University of Uyo Akwa Ibom State Uyo Akwa Ibom State Nigeria Department of Chemical Engineering and Analytical Science University of Manchester Manchester UK

The goal of this study was to determine whether mutation of the Mn-binding site of wild-type recombinant Phlebia radiata manganese peroxidase 3 affected the pH-dependence kinetic parameters. pH range investigated was 2.5 – 12.0. The catalytic efficiency of the mutant enzymes at high and low pH in comparison to the wild-type was investigated using standard rPr-MnP3 protocol. Wild-type recombinant Phlebia radiata MnP3 enzyme showed optimal activity with Mn (II) as substrate at pH 5.0 and remained moderately active (approximately 40%) in the pH range of 6.0 - 9.0. The rPr-MnP3 mutants’ maximum activity ranged between 5.5 and 8.0. Wild-type and mutants rPr-MnP3 enzymes exhibited a similar pH profile with optimum pH of 3.0 for ABTS oxidation. Mutation has severely decreased the catalytic efficiency for Mn (II) oxidation at pH 5.0. The rPr-MnP3 enzymes showed enhanced affinity for Mn (II) at alkaline pH and a more alkaline range for catalysis than ever reported for any manganese peroxidase. This study reveals that at higher pH, rPr-MnP3 can function with alternative ligands in the Mn (II) site and does not have an absolutely obligate requirement for an all carboxylate ligand set. These results further strongly confirm that Mn2+ binding site is the only productive catalytic site for Mn (II) oxidation.

关键词： pH-Dependence Phlebia radiata manganese peroxidase Wild-Type Mutants Recombinant Enzyme

The Roles of pH in the Modification of Wild-Type Recombinant Phlebia radiata manganese peroxidase 3 Activities and Stability of Secondary Structures

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American Journal of Molecular Biology 2022年第4期12卷 158-180页

作者： Usenobong F. Ufot Imeh J. Okop Mfoniso P. Uko Imekan I. Akpan Khasim Cali Monday I. Akpanabiatu Department of Biochemistry Faculty of Biological Sciences Akwa Ibom State University Uyo Nigeria Department of Chemistry Faculty of Biological Sciences Akwa Ibom State University Uyo Nigeria Department of Microbiology Faculty of Biological Sciences Akwa Ibom State University Uyo Nigeria Department of Zoology Faculty of Biological Sciences Akwa Ibom State University Uyo Nigeria Department of Chemical Engineering and Analytical Science University of Manchester Manchester UK Department of Biochemistry Faculty of Sciences University of Uyo Uyo Nigeria

This investigation is aimed at understanding the specific role of pH and calcium ions on the activity and stability of wild-type recombinant Phlebia radiata manganese peroxidase 3 (rPr-MnP3). The pH-dependent cycle of reactions for rPr-MnP3 was evaluated by investigating time-dependent changes in the activity and electronic absorption spectrum of rPr-MnP3.The rPr-MnP3 had maximum efficacy (kcat/Km) for Mn (II) oxidation at pH 5.0 and 3.0 for oxidation of ABTS. Raising the pH of a solution of resting rPr-MnP3 from pH 6.7 (form XH) to pH 8.6 (form X−), a rapid alkaline transition occurs. Leaving the X− form of the enzyme at pH 8.6, it slowly becomes converted to a third form of the enzyme Y−, which returned to the original XH form of the enzyme at pH 6.7. Recovery of form XH from form Y− occurred through an intermediate Z form. The pH inactivation of rPr-MnP3 followed first-order kinetics. The rate of formation of XH from Z is pH-dependent and biphasic in nature, with measured rate constants (k) = 0.25 min−1, and half-life (T1/2) = 2.8 min. The pH-dependent properties observed may be indicative of a greater degree of conformational flexibility at rPr-MnP3 active site due to disruption of the haem-linked hydrogen-bonding network in the distal haem pocket. Calcium ions were observed to significantly stabilised the enzyme’s spectral features and reduce the loss of activity during the alkaline pH transition. Calcium ions enhance the recovery of the initial activity but cannot prevent the final time-dependent irreversible denaturation and aggregation.

关键词： Phlebia radiata manganese peroxidase pH-Dependence Inactivation Conformation

Cloning and characterization of three novel manganese peroxidase genes from the ligninolytic basidiomycete Trametes gibbosa

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Cloning and characterization of three novel manganese peroxi...

Evaluation of ligninolytic activity in spent mushroom substrate from four cultivated mushrooms

中国菌物学会第五届会员代表大会暨2011年学术年会

作者： YAN Hong-Bo CHI Yu-Jie~* WU Shu-Jing (Key Laboratory of Forest Tree Genetics Breeding and Biotechnology,Northeast Forestry University,Harbin 150040,China.)

＜正＞In this study,three full-length manganese peroxidase（MnP） genes from white-rot fungus Trametes gibbosa,termed Tgmnp1,Tgmnp2,and Tgmnp3,were cloned and sequenced.The predicted open reading frames （ORFs） are 1,098-,1,095-,and 1,101 -bp long and all be interrupted by five introns.The deduced amino acid sequences encode manganese peroxidases containing 365,364,and 366 residues,respectively.The MnP gene Tgmnpl shares highest similarity（84%） to mnp from Trametes versicolor（BAB03464）,Tgmnp2 reveals 88% similarity to mnp from T.versicolor（CAG33918）,and Tgmnp3 showed the highest identity（89%） to MnP from T versicolor（BAB03464）.Consistent with the peroxidase mechanism of MnP,the proximal histidine,the distal histidine and the distal arginine,and the aromatic binding site（L/V/I-P-X-P） are conserved.The intron splice junction sequences as well as the putative internal lariat formation sites in three mnps adhere to the GT-AG and CTRAY rules,respectively.The 5’ upstream and 3’ downstream non-coding flanking regions of three mnp genes were also amplified using genome walking-PCR,respectively.All promoters contain putative TATAA elements and some inverted CCAAT element as well.Further more,SP-1,AP-1,AP-2 sites and several putative metal response and heat-shock elements（MRE and HSE） were identified in each sequence.

关键词： Trametes gibbosa manganese peroxidase gene cloning sequences analysis

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Journal of Bioresources and Bioproducts 2022年第4期7卷 288-294页

作者： Ana Marión Pérez-Chávez María Melisa Alberti Edgardo Albertó Laboratory of Mycology and Mushroom Cultivation.Instituto Tecnológico de Chascomús(INTECH) Universidad Nacional de San Martín(UNSAM)-Consejo Nacional de Investigaciones Científicas y Técnicas(CONICET)Intendente Marino AveCC 164.7130ChascomúsBuenos AiresArgentina

Spent mushroom substrate(SMS)is an abundant residue generated by the mushroom industry,which is mostly discarded.In this study,the SMS of four cultivated mushrooms were evaluated as potential sources of ligninolytic enzymes.Pleurotus ostreatus,P.eryngii,P.djamor and Ganoderma lucidum were cultivated in two different substrates to determine growth,mushroom yields and ligninolytic activity of laccase(Lac)and manganese peroxidase(MnP).Maximum activities in the SMS were 3.731 U/g Lac and 0.191 U/g MnP,both for P.eryngii.Colonized mushroom substrates were also analyzed,and higher activities were found in almost all samples.A correlation test between mushroom yields and ligninolytic activities of each culture was made,and we found that high enzymatic activity in the substrate did not result in high mushroom productivity or vice versa.The SMS was a good source of ligninolytic enzymes.Enzymatic activity depended on the mushroom species and its affinity to the substrate,and it was not influenced by the mushroom yields.Production of mushrooms in diverse lignocellulosic substrates is gaining interest,and ob-taining ligninolytic enzymes from residual SMS is an excellent alternative in the circular economy concept.

关键词： Laccase manganese peroxidase Biological efficiency Pleurotus spp Ganoderma lucidum Circular economy

Effect of heavy metals and phenol on bacterial decolourisation and COD reduction of sucrose-aspartic acid Maillard product

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Journal of Environmental Sciences 2013年第1期25卷 172-180页

作者： Sangeeta Yadav Ram Chandra Department of Environmental Microbiology School for Environmental SciencesBabasaheb Bhimrao Ambedkar University (A Central University)

Melanodins are amino-carbonyl complex, predominantly present in sugarcane molasses based distillery wastewater as major source of colourant. The microbial decolourisafion of melanoidin is a challenge due to its binding property with other co-pollutants of distillery waste. Results revealed that the presence of Zn2＋（2.00-20.00 mg/L） in melanoidin solution （1200 mg/L） stimulated the bacterial growth and sucrose-aspartic acid Maillard product （SAA） decolourisation as compared to control, while Fe3＋ and Mn2＋ at the same concentration inhibited the process. However, the presence of phenol （100 mg/L） along with Zn2＋, Fe3＋ and Mn2＋ suppressed the bacterial growth, SAA decolourisation and MnP activity. The shrinkage and reduced number of bacterial cell count at higher concentration of heavy metals in presence of phenol was also observed under scanning electron microscope.

关键词： degradation manganese peroxidase melanoidin

Ligninolytic enzymes production by endophytic fungus Diaporthe phaseolorum(Desm.)Sacc.under the influence of different carbon and nitrogen sources

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Studies in Fungi 2021年第1期6卷 531-542页

作者： Kumar V Prasher IB Mycology and Plant Pathology Lab. Department of BotanyPanjab University ChandigarhChandigarh-160014India

Endophytic fungi are being investigated for their ability to create industrially relevant secondary metabolites.In recent years,there has been a surge in interest in these fungi as a source of novel enzymes,particularly hydrolytic enzymes.The present study investigated the effect of different carbon,organic and inorganic nitrogens on the growth and ligninolytic enzyme production by the endophytic fungus Diaporthe phaeolorum.The fungus was isolated from the leaves of Dillenia indica and analyzed by morpho-molecular basis.The fungus showed promising results for in vitro production of ligninolytic enzymes.Sucrose was the most favorable carbon compound for growth among all the carbon compounds tested.It displayed maximum lignin peroxidase(Lip)activity in fructose(3.5 U/ml),followed by pectin(2.60 U/ml)and glucose(2.53 U/ml).Glucose gave the highest manganese peroxidase(MnP)activity i.e.,6.88 U/ml followed by starch,sucrose and raffinose.Similarly,the maximum laccase activity was 44.5 U/ml in pectin.Potassium nitrate and L-asparagine were the best inorganic and organic nitrogen for growth.In the case of ligninolytic enzyme production,ammonium acetate and ammonium phosphate were the best media for LiP and MnP,whereas laccase production was highest in ammonium nitrate supplemented medium.In organic nitrogen sources,medium supplemented with DL-tryptophan gave the highest Lip production,whereas MnP and laccase production was observed in the medium containing L-tyrosine and L-asparagine.To the best of our knowledge,this is the first report related to the growth and ligninolytic enzyme production by Diaporthe phaseolorum.The findings from the study will assist researchers in improving the production of ligninolytic enzymes by this fungus under in vitro conditions on an industrial scale.

关键词： Hydrolytic enzymes Industrially In vitro manganese peroxidase Morpho molecular analysis