scholarly journals Structural and biochemical characterization of the dual substrate recognition of the (R)-selective amine transaminase fromAspergillus fumigatus

FEBS Journal ◽  
2014 ◽  
Vol 282 (2) ◽  
pp. 407-415 ◽  
Author(s):  
Lilly Skalden ◽  
Maren Thomsen ◽  
Matthias Höhne ◽  
Uwe T. Bornscheuer ◽  
Winfried Hinrichs
Keyword(s):  
Biochemical Characterization ◽  
Substrate Recognition ◽  
Dual Substrate

Biochemical characterization of two chitinases from Bacillus cereus sensu lato B25 with antifungal activity against Fusarium verticillioides P03

2020 ◽  
Author(s):  
Estefanía Morales-Ruiz ◽  
Ricardo Priego-Rivera ◽  
Alejandro Miguel Figueroa-López ◽  
Jesús Eduardo Cazares-Álvarez ◽  
Ignacio E Maldonado-Mendoza
Keyword(s):  
Bacillus Cereus ◽  
Biochemical Characterization ◽  
Fusarium Verticillioides ◽  
Expression System ◽  
Phytopathogenic Fungi ◽  
Fungal Cell ◽  
Synthetic Pesticides ◽  
Bacillus Cereus Sensu Lato ◽  
Dual Substrate

Abstract Bacterial chitinases are a subject of intense scientific research due to their biotechnological applications, particularly their use as biological pesticides against phytopathogenic fungi as a green alternative to avoid the use of synthetic pesticides. Bacillus cereus sensu lato B25 is a rhizospheric bacterium that is a proven antagonist of Fusarium verticillioides, a major fungal pathogen of maize. This bacterium produces two chitinases that degrade the fungal cell wall and inhibit its growth. In this work, we used a heterologous expression system to purify both enzymes to investigate their biochemical traits in terms of Km, Vmax, optimal pH and temperature. ChiA and ChiB work as exochitinases, but ChiB exhibited a dual substrate activity and it is also an endochitinase. In this work, the direct addition of these chitinases inhibited fungal conidial germination and therefore they may play a major role in the antagonism against F. verticillioides.

scholarly journals Co-occurrence of analogous enzymes determines evolution of a novel (βα)8-isomerase sub-family after non-conserved mutations in flexible loop

2016 ◽  
Vol 473 (9) ◽  
pp. 1141-1152 ◽  
Author(s):  
Ernesto A. Verduzco-Castro ◽  
Karolina Michalska ◽  
Michael Endres ◽  
Ana L. Juárez-Vazquez ◽  
Lianet Noda-García ◽  
...  
Keyword(s):  
Biochemical Characterization ◽  
Isomerase Activity ◽  
Corynebacterium Species ◽  
Missing Gene ◽  
The Relationship ◽  
Substrate Affinities ◽  
Dual Substrate

We investigate the evolution of co-occurring analogous enzymes involved in L-tryptophan and L-histidine biosynthesis in Actinobacteria. Phylogenetic analysis of trpF homologues, a missing gene in certain clades of this lineage whose absence is complemented by a dual-substrate HisA homologue, termed PriA, found that they fall into three categories: (i) trpF-1, an L-tryptophan biosynthetic gene horizontally acquired by certain Corynebacterium species; (ii) trpF-2, a paralogue known to be involved in synthesizing a pyrrolopyrrole moiety and (iii) trpF-3, a variable non-conserved orthologue of trpF-1. We previously investigated the effect of trpF-1 upon the evolution of PriA substrate specificity, but nothing is known about the relationship between trpF-3 and priA. After in vitro steady-state enzyme kinetics we found that trpF-3 encodes a phosphoribosyl anthranilate isomerase. However, mutation of this gene in Streptomyces sviceus did not lead to auxothrophy, as expected from the biosynthetic role of trpF-1. Biochemical characterization of a dozen co-occurring TrpF-2 or TrpF-3, with PriA homologues, explained the prototrophic phenotype, and unveiled an enzyme activity trade-off between TrpF and PriA. X-ray structural analysis suggests that the function of these PriA homologues is mediated by non-conserved mutations in the flexible L5 loop, which may be responsible for different substrate affinities. Thus, the PriA homologues that co-occur with TrpF-3 represent a novel enzyme family, termed PriB, which evolved in response to PRA isomerase activity. The characterization of co-occurring enzymes provides insights into the influence of functional redundancy on the evolution of enzyme function, which could be useful for enzyme functional annotation.

Plant Pathology Diagnosed by X-Ray Microanalysis

1987 ◽  
Vol 45 ◽  
pp. 974-975
Author(s):  
J. H. Resau ◽  
N. Howell ◽  
S. H. Chang
Keyword(s):  
Electron Microscopy ◽  
Plant Pathology ◽  
Biochemical Characterization ◽  
Nutrient Deficiency ◽  
Green Leaf ◽  
Parasitic Infestation ◽  
X Ray

Spinach grown in Texas developed “yellow spotting” on the peripheral portions of the leaves. The exact cause of the discoloration could not be determined as there was no evidence of viral or parasitic infestation of the plants and biochemical characterization of the plants did not indicate any significant differences between the yellow and green leaf portions of the spinach. The present study was undertaken using electron microscopy (EM) to determine if a micro-nutrient deficiency was the cause for the discoloration.Green leaf spinach was collected from the field and sent by express mail to the EM laboratory. The yellow and equivalent green portions of the leaves were isolated and dried in a Denton evaporator at 10-5 Torr for 24 hrs. The leaf specimens were then examined using a JEOL 100 CX analytical microscope. TEM specimens were prepared according to the methods of Trump et al.

Interaction effect of rootstocks on gas exchange parameters, biochemical changes and nutrientstatus in Sauvignon Blanc winegrapes

2014 ◽  
Vol 3 (3) ◽  
pp. 218-225
Author(s):  
R. G. Somkuwar ◽  
M. A. Bhange ◽  
A. K. Upadhyay ◽  
S. D. Ramteke
Keyword(s):  
Biochemical Characterization ◽  
Reducing Sugar ◽  
Wine Grape ◽  
Gas Exchange Parameters ◽  
Food Material ◽  
Total Carbohydrates ◽  
Salt Creek ◽  
Grape Varieties ◽  
Photosynthetic Activities

SauvignonBlanc wine grape was characterized for their various morphological, physiological and biochemical parameters grafted on different rootstocks. Significant differences were recorded for all the parameters studied. The studies on vegetative parameters revealed that the rootstock influences the vegetative growth thereby increasing the photosynthetic activities of a vine. The highest photosynthesis rate was recorded in 140-Ru grafted vine followed by Fercal whereas the lowest in Salt Creek rootstock grafted vines.The rootstock influenced the changes in biochemical constituents in the grafted vine thereby helping the plant to store enough food material. Significant differences were recorded for total carbohydrates, proteins, total phenols and reducing sugar. The vines grafted on1103-Pshowed highest carbohydrates and starch followed by 140-Ru,while the least amount of carbohydrates were recorded in 110-R and Salt Creek grafted vines respectively.Among the different rootstock graft combinations, Fercal showed highest amount of reducing sugar, proteins and phenols, followed by 1103-P and SO4, however, the lowest amount of reducing sugar, proteins and phenols were recorded with 110-R grafted vines.The vines grafted on different rootstocks showed changes in nutrient uptake. Considering this, the physico-biochemical characterization of grafted vine may help to identify particularrootstocks combination that could influence a desired trait in commercial wine grape varieties after grafting.

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