Dishisha T

References (2)

Title : Comparative Structural Analysis of Different Mycobacteriophage-Derived Mycolylarabinogalactan Esterases (Lysin B) - Korany_2019_Biomolecules_10_
Author(s) : Korany AH , Abouhmad A , Bakeer W , Essam T , Amin MA , Hatti-Kaul R , Dishisha T
Ref : Biomolecules , 10 : , 2019
Abstract : Mycobacteriophage endolysins have emerged as a potential alternative to the current antimycobacterial agents. This study focuses on mycolylarabinogalactan hydrolase (LysB) enzymes of the alpha/beta-hydrolase family, which disrupt the unique mycolic acid layer of mycobacterium cell wall. Multiple sequence alignment and structural analysis studies showed LysB-D29, the only enzyme with a solved three-dimensional structure, to share several common features with esterases (lacking lid domain) and lipases (acting on long chain lipids). Sequence and structural comparisons of 30 LysB homology models showed great variation in domain organizations and total protein length with major differences in the loop-5 motif harboring the catalytic histidine residue. Docking of different p-nitrophenyl ligands (C4-C18) to LysB-3D models revealed that the differences in length and residues of loop-5 contributed towards wide diversity of active site conformations (long tunnels, deep and superficial funnels, shallow bowls, and a narrow buried cave) resembling that of lipases, cutinases, and esterases. A set of seven LysB enzymes were recombinantly produced; their activity against p-nitrophenyl esters could be related to their active site conformation and acyl binding site. LysB-D29 (long tunnel) showed the highest activity with long chain p-nitrophenyl palmitate followed by LysB-Omega (shallow bowl) and LysB-Saal (deep funnel).
ESTHER : Korany_2019_Biomolecules_10_
PubMedSearch : Korany_2019_Biomolecules_10_
PubMedID: 31892223

Title : Selective oxidation of trimethylolpropane to 2,2-bis(hydroxymethyl)butyric acid using growing cells of Corynebacterium sp. ATCC 21245 - Sayed_2016_J.Biotechnol_221_62
Author(s) : Sayed M , Dishisha T , Sayed WF , Salem WM , Temerk HA , Pyo SH
Ref : J Biotechnol , 221 :62 , 2016
Abstract : Multifunctional chemicals including hydroxycarboxylic acids are gaining increasing interest due to their growing applications in the polymer industry. One approach for their production is a biological selective oxidation of polyols, which is difficult to achieve by conventional chemical catalysis. In the present study, trimethylolpropane (TMP), a trihydric alcohol, was subjected to selective oxidation using growing cells of Corynebacterium sp. ATCC 21245 as a biocatalyst and yielding the dihydroxy-monocarboxylic acid, 2,2-bis(hydroxymethyl)butyric acid (BHMB). The study revealed that co-substrates are crucial for this reaction. Among the different evaluated co-substrates, a mixture of glucose, xylose and acetate at a ratio of 5:5:2 was found optimum. The optimal conditions for biotransformation were pH 8, 1v/v/m airflow and 500rpm stirring speed. In batch mode of operation, 70.6% of 5g/l TMP was converted to BHMB in 10 days. For recovery of the product the adsorption pattern of BHMB to the anion exchange resin, Ambersep((R)) 900 (OH(-)), was investigated in batch and column experiments giving maximum static and dynamic binding capacities of 135 and 144mg/g resin, respectively. BHMB was separated with 89.7% of recovery yield from the fermentation broth. The approach is applicable for selective oxidation of other highly branched polyols by biotransformation.
ESTHER : Sayed_2016_J.Biotechnol_221_62
PubMedSearch : Sayed_2016_J.Biotechnol_221_62
PubMedID: 26804932
Gene_locus related to this paper: 9myco-a0a1p8xg62