Insilico Characterization and Homology Modeling of Arabitol Dehydrogenase (ArDH) from Candida albican

Abstract

Background: Arabitol dehydrogenase (ArDH) is involved in the production of different sugar alcohols like arabitol, sorbitol, mannitol, erythritol and xylitol by using five carbon sugars as substrate. Arabinose, d-ribose, d-ribulose, xylose and d-xylulose are known substrate of this enzyme. ArDH is mainly produced by osmophilic fungi for the conversion of ribulose to arabitol under stress conditions. Recently this enzyme has been used by various industries for the production of pharmaceutically important sugar alcohols form cheap source than glucose. But the information at structure level as well as its binding energy analysis with different substrates was missing. Results: The present study was focused on sequence analysis, insilico characterization and substrate binding analysis of ArDH from a fungus specie candida albican. Sequence analysis and physicochemical properties showed that this protein is highly stable, negatively charged and having more hydrophilic regions, these properties made this enzyme to bind with number of five carbon sugars as substrate. The predicted 3D model will helpful for further structure based studies. Docking analysis provided free energies of binding of each substrate from a best pose as arabinose -9.8224calK/mol, dribose -11.3701Kcal/mol, d-ribulose -8.9230Kcal/mol, xylose -9.7007Kcal/mol and d-xylulose 9.7802Kcal/mol. Conclusion: Our study provided insight information of structure and interactions of ArDH with its substrate. These results obtained from this study clearly indicate that d-ribose is best substrate for ArDH for the production of sugar alcohols. This information will be helpful for better usage of this enzyme for hyper-production of sugar alcohols by different industries.

Structure activity relationship (SAR) and quantitative structure activity relationship (QSAR) studies showed plant flavonoids as potential inhibitors of dengue NS2B-NS3 protease

“…This structure was subjected to 3D protonation and energy minimization using parameters like (gradient: 0.05, Force Field: MMFF94X + Solvation) using MOE Program. For docking the minimized structure was used as the receptor protein [ 21 ].…”

Metabolic engineering of the chloroplast genome reveals that the yeast ArDH gene confers enhanced tolerance to salinity and drought in plants

“…Enzyme activity was different in different plants (T1, T2, T3, and T4 samples) due to their heterogenetic nature though given readings are an average of three samples. The high ARDH enzyme activity was observed in fully expanded leaves of potted plants (T4 homoplasmic transgenic plants) compared to primary heteroplasmic transgenic plants, as described ( Sarwar, 2007 , 2013 ). This was due to two reasons: first, copy number for transgene was increased toward homoplasmy.…”

“…Arabitol dehydrogenase activity was measured in crude extracts of leaves from wild-type and transgenic plants as previously described for yeast by Wong et al (1995) and on heteroplasmic tobacco seedlings ( Sarwar, 2007 , 2013 ). The rate of reduction of NAD to NADH by ARDH enzyme in the presence of D -arabitol was measured by the reduction of MTT (3, 5 dimethylethiazol -2-yl 2, 5 dimethyle tetrazolium bromide) in the solution.…”

“…First generation heteroplasmic plants were grown in pots for seed setting and variable degrees of tolerance to NaCl were observed ( Sarwar, 2007 , 2013 ) hence, primary transgenic plants growing under in vitro conditions were subjected to a number of selection and regeneration rounds to purify transplastomes to homoplasmic level since the process requires 16–17 cell divisions ( Moll et al, 1990 ; Khan and Maliga, 1999 ). Consequently, confirmed homoplasmic plants were recovered and grown in pots for seed setting.…”

“…The spectinomycin-resistant plants were developed in the laboratory of the corresponding author and were analyzed for transgene integration into the plastome (Plastid genome). Later on, an M Phil student ( Sarwar, 2007 ) was given a task to analyze the putative transgenic plants where preliminary studies were carried out to optimize conditions for enzyme and stress assays ( Sarwar, 2007 , 2013 ). Encouraged from preliminary results the putative transgenic plants were purified to homoplasmic level through sequential rounds of regeneration on spectinomycin-containing medium.…”