Exploiting Mannuronan C-5 Epimerases in Commercial Alginate Production
نویسندگان
چکیده
منابع مشابه
Construction and analyses of hybrid Azotobacter vinelandii mannuronan C-5 epimerases with new epimerization pattern characteristics.
The secreted mannuronan C-5 epimerases from Azotobacter vinelandii form a family of seven homologous modular type enzymes, which appear to have evolved through duplications and point mutations in the individual modules. The catalytic A modules of these enzymes are responsible for generating the characteristic sequence distribution patterns of G residues in the industrially important polymer alg...
متن کاملBiochemical analysis of the processive mechanism for epimerization of alginate by mannuronan C-5 epimerase AlgE4.
The enzymes mannuronan C-5 epimerases catalyse the in-chain epimerisation of beta-D-mannuronic acid to alpha-L-guluronic acid in the last step of alginate biosynthesis. The recombinant C-5 epimerase AlgE4, encoded by the soil bacteria Azotobacter vinelandii and expressed in Escherichia coli, exhibits a non-random mode of action when acting on mannuronan and alginates of various monomeric compos...
متن کاملMode of action and subsite studies of the guluronan block-forming mannuronan C-5 epimerases AlgE1 and AlgE6.
AlgE1, AlgE5 and AlgE6 are members of a family of mannuronan C-5 epimerases encoded by the bacterium Azotobacter vinelandii, and are active in the biosynthesis of alginate, where they catalyse the post-polymerization conversion of beta-D-mannuronic acid (M) residues into alpha-L-guluronic acid residues (G). All enzymes show preference for introducing G-residues neighbouring a pre-existing G. Th...
متن کاملCharacterization of mannuronan C-5-epimerase genes from the brown alga Laminaria digitata.
Alginate is an industrially important polysaccharide obtained commercially by harvesting brown algae. The final step in alginate biosynthesis, the epimerization of beta-1,4-d-mannuronic acid to alpha-1,4-l-guluronic acid, a structural change that controls the physicochemical properties of the alginate, is catalyzed by the enzyme mannuronan C-5-epimerase. Six different cDNAs with homology to bac...
متن کاملThe Pseudomonas fluorescens AlgG protein, but not its mannuronan C-5-epimerase activity, is needed for alginate polymer formation.
Bacterial alginates are produced as 1-4-linked beta-D-mannuronan, followed by epimerization of some of the mannuronic acid residues to alpha-L-guluronic acid. Here we report the isolation of four different epimerization-defective point mutants of the periplasmic Pseudomonas fluorescens mannuronan C-5-epimerase AlgG. All mutations affected amino acids conserved among AlgG-epimerases and were clu...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Marine Drugs
سال: 2020
ISSN: 1660-3397
DOI: 10.3390/md18110565