Strategic aromatic residues in the catalytic cleft of the xyloglucanase MtXgh74 modifying thermostability, mode of enzyme action, and viscosity reduction ability.

The thermostable endo-processive xyloglucanase MtXgh74 from Myceliophthora thermophila was used to study the influence of aromatic amino acids in the catalytic cleft on the mode of action and the ability of enzyme to reduce xyloglucan viscosity. The enzyme derivative Mut I with mutations W64A/W67A in the "negative" subsites of the catalytic cleft resulted in a 5.5-fold increase of the K value.

Novel endo-(1,4)-β-glucanase Bgh12A and xyloglucanase Xgh12B from Aspergillus cervinus belong to GH12 subgroup I and II, respectively.

In spite of intensive exploitation of aspergilli for the industrial production of carbohydrases, little is known about hydrolytic enzymes of fungi from the section Cervini. Novel glycoside hydrolases Bgh12A and Xgh12B from Aspergillus cervinus represent examples of divergent activities within one enzyme family and belong to the GH12 phylogenetic subgroup I (endo-(1,4)-β-glucanases) and II (endo-xyloglucanases), respectively. The bgh12A and xgh12B genes were identified in the unsequenced genome of A.

Thermostable multifunctional GH74 xyloglucanase from Myceliophthora thermophila: high-level expression in Pichia pastoris and characterization of the recombinant protein.

A xyloglucanase of the GH74 family was identified in the thermophilic fungus strain Myceliophthora thermophila VKPM F-244, and its gene sequence was optimized for cloning and expression in Pichia pastoris. The recombinant xyloglucanase MtXgh74 exhibited the highest activity toward tamarind seed xyloglucan with a K value of 0.51 ± 0.

Draft Genome Sequence of Escherichia coli Strain VKPM B-10182, Producing the Enzyme for Synthesis of Cephalosporin Acids.

Escherichia coli strain VKPM B-10182, obtained by chemical mutagenesis from E. coli strain ATCC 9637, produces cephalosporin acid synthetase employed in the synthesis of β-lactam antibiotics, such as cefazolin. The draft genome sequence of strain VKPM B-10182 revealed 32 indels and 1,780 point mutations that might account for the improvement in antibiotic synthesis that we observed.

Reconstructing the clostridial n-butanol metabolic pathway in Lactobacillus brevis.

A Lactobacillus brevis strain with the ability to synthesize butanol from glucose was constructed by metabolic engineering. The genes crt, bcd, etfB, etfA, and hbd, composing the bcs-operon, and the thl gene encode the enzymes of the lower part of the clostridial butanol pathway (crotonase, butyryl-CoA-dehydrogenase, two subunits of the electron transfer flavoprotein, 3-hydroxybutyryl-CoA dehydrogenase, and thiolase) of Clostridium acetobutylicum. They were cloned into the Gram-positive/Gram-negative shuttle plasmid vector pHYc.