The present invention discloses a directionally modified glucosamine synthase mutant and its application. The amino acid sequence of the glucosamine synthase mutant is as shown in sequence list SEQ ID No. 1, and the nucleotide sequence is as shown in sequence list SEQ ID No. 2. The genetic engineering bacteria of glucosamine synthase is successfully constructed. In order to improve the tolerance of recombinant bacteria against glucosamine, the glucosamine synthase is directionally modified. A glucosamine synthase mutant is selected from the mutant library via high-throughput screening method, the amino acid changes in the mutant induces the spatial conformational change in the enzyme, so as enlarged the region where the enzyme and substrate combines, therefor the combination efficiency of the enzyme and the substrate is increased. The glucosamine synthase of the present invention has various advantages, such as rich in raw material of glucose, and a convenient subsequent extraction.

An antibiotic FIIRV 104/18 complex comprising factors F793, F795, F797, F813 and F683, of formula (I), wherein R represents a glycosidic radical as defined in the specification, the isolated individual factors, a method for their production by cultivation of Dactylosporangium FIIRV sp. 104/18 DSM 32068 under aerobic conditions, and pharmaceutical formulations containing them as active ingredient and their use in the treatment of bacterial infections, caused by bacteria of at least one of the genera Enterococci, Streptococci, Staphylococci and Moraxella, including bacteria of multi resistant strains, in particular Staphylococcus spp., Streptococcus spp, and Enterococcus spp. resistant to methicillin and/or vancomycin.

##STR00001##

An antibiotic FIIRV 104/18 complex comprising factors F793, F795, F797, F813 and F683, of formula (I), wherein R represents a glycosidic radical as defined in the specification, the isolated individual factors, a method for their production by cultivation of Dactylosporangium FIIRV sp. 104/18 DSM 32068 under aerobic conditions, and pharmaceutical formulations containing them as active ingredient and their use in the treatment of bacterial infections, caused by bacteria of at least one of the genera Enterococci, Streptococci, Staphylococci and Moraxella, including bacteria of multi resistant strains, in particular Staphylococcus spp., Streptococcus spp, and Enterococcus spp. resistant to methicillin and/or vancomycin.

##STR00001##

The present invention discloses a directionally modified glucosamine synthase mutant and its application. The amino acid sequence of the glucosamine synthase mutant is as shown in sequence list SEQ ID No. 1, and the nucleotide sequence is as shown in sequence list SEQ ID No. 2. The genetic engineering bacteria of glucosamine synthase is successfully constructed. In order to improve the tolerance of recombinant bacteria against glucosamine, the glucosamine synthase is directionally modified. A glucosamine synthase mutant is selected from the mutant library via high-throughput screening method, the amino acid changes in the mutant induces the spatial conformational change in the enzyme, so as enlarged the region where the enzyme and substrate combines, therefor the combination efficiency of the enzyme and the substrate is increased. The glucosamine synthase of the present invention has various advantages, such as rich in raw material of glucose, and a convenient subsequent extraction.

A method for preparing glucosamine includes the steps of converting fructose-6-phosphate (F6P) and an ammonium salt to glucosamine-6-phosphate (GlcN6P) under the catalysis of glucosamine-6-phosphate deaminase (EC 3.5.99.6, GlmD); and producing glucosamine (GlcN) by the dephosphorylation of GlcN6P under the catalysis of an enzyme capable of catalyzing the dephosphorylation. Such a method can be used to prepare glucosamine by in vitro enzymatic biosystem.

The present invention relates to a method for the stereo-selective production of pentostatin comprising an enzymatic transglycosylation reaction between 6,7-dihydroimidazo-[4,5-d]-[1,3]diazepin-8(3H)-one and a 2-deoxyribonucleoside, followed by an ruthenium-catalyzed asymmetric transfer hydrogenation.

The present invention relates to a method for the stereo-selective production of pentostatin comprising an enzymatic transglycosylation reaction between 6,7-dihydroimidazo-[4,5-d]-[1,3]diazepin-8(3H)-one and a 2-deoxyribonucleoside, followed by an ruthenium-catalyzed asymmetric transfer hydrogenation.

A method or producing amino sugar (containing) products using metabolically engineered microorganisms is disclosed, wherein the conversion of UDP-N-acetylglucosamine to cell envelope precursors and molecules is reduced by altering the activity of enzymes involved in the synthesis of cell envelope precursors and molecules.

A glycoside hydrolase, relating to the technical field of enzyme engineering/gene engineering. Provided are an enzyme of a GH112 glycoside hydrolase family, and an application of synthesizing human milk oligosaccharides (HMOs) by using an enzyme of a GH112 glycoside hydrolase family. A synthesis reaction is catalyzed by using the enzyme of the glycoside hydrolase family 112 (GH112) that is classified according to a Carbohydrate-Active-Enzymes (CAZy) database (http://www.cazy.org); and lacto-N-tetraose (LNT) is generated in an aqueous solution comprising lactose and/or galactose and/or galactose-1-phosphate and lacto-N-triose (LNTII). The enzyme of the glycoside hydrolase family 112 (GH112), and the preparation method therefor and the application thereof provided by the present invention have economic and social values.

A glycoside hydrolase, relating to the technical field of enzyme engineering/gene engineering. Provided are an enzyme of a GH112 glycoside hydrolase family, and an application of synthesizing human milk oligosaccharides (HMOs) by using an enzyme of a GH112 glycoside hydrolase family. A synthesis reaction is catalyzed by using the enzyme of the glycoside hydrolase family 112 (GH112) that is classified according to a Carbohydrate-Active-Enzymes (CAZy) database (http://www.cazy.org); and lacto-N-tetraose (LNT) is generated in an aqueous solution comprising lactose and/or galactose and/or galactose-1-phosphate and lacto-N-triose (LNTII). The enzyme of the glycoside hydrolase family 112 (GH112), and the preparation method therefor and the application thereof provided by the present invention have economic and social values.