Bacterial 1,4-α-glucan branching enzymes: characteristics, preparation and commercial applications.

The 1,4-α-glucan branching enzymes (GBEs) are ubiquitously distributed in animals, microorganisms and plants. These enzymes modify the structure of both starch and glycogen; changing the frequency and position of branches by forming new α-1,6-glucosidic linkages. In organisms, controlling the number and distribution of branches is an irreplaceable process that maintains the physiological state of starch and glycogen in the cell.

Leu600 mutations decrease product inhibition of the β-cyclodextrin glycosyltransferase from Bacillus circulans STB01.

The limits that cyclodextrin products impose on their industrial production from starch by cyclodextrin glycosyltransferases (CGTases) are a severe problem. In this paper, mutants at residue Leu600 of the β-CGTase from Bacillus circulans STB01 were constructed in an effort to decrease the product inhibition exhibited by β-cyclodextrin. A kinetic analysis of the inhibition of the wild-type and mutant β-CGTases by β-cyclodextrin revealed that the mutations do not alter the inhibition mode, which is mixed-type.

Maltooligosaccharide-forming amylase: Characteristics, preparation, and application.

As member of glycosyl hydrolase family 13, maltooligosaccharide-forming amylases (MFAses) are specific and interesting because of their capacity to hydrolyze starch into functional maltooligosaccharides, which are usually composed of 2-10 α-d-glucopyranosyl units linked by α-1,4 glycosidic linkages. MFAses have been extensively studied during recent decades, and have shown promise in various industrial applications. This review begins by introducing the potential uses of maltooligosaccharides.

Asp577 mutations enhance the catalytic efficiency of cyclodextrin glycosyltransferase from Bacillus circulans.

The amino acid residue Asp 577 is located in calcium-binding site III (CaIII) of the cyclodextrin glycosyltransferase (EC 2.4.1.

A novel glucose 6-phosphate isomerase from Listeria monocytogenes.

D-Arabinose 5-phosphate isomerases (APIs) catalyze the interconversion of D-ribulose 5-phosphate and D-arabinose 5-phosphate (A5P). A5P is an intermediate in the biosynthesis of 3-deoxy-D-manno-octulosonate (Kdo), an essential component of lipopolysaccharide, the lipopolysaccharide found in the outer membrane of Gram-negative bacteria. The genome of the Gram-positive pathogen Listeria monocytogenes contains a gene encoding a putative sugar isomerase domain API, Q723E8, with significant similarity to c3406, the only one of four APIs from Escherichia coli CFT073 that lacks a cystathionine-β-synthase domain.

Polyethylene glycols enhance the thermostability of β-cyclodextrin glycosyltransferase from Bacillus circulans.

We investigated the ability of six polyethylene glycols (PEGs), with molecular weights ranging from 400 to 20,000 Da, to enhance the thermostability of β-cyclodextrin glycosyltransferase (β-CGTase) from Bacillus circulans. We found that PEGs with different molecular weights could activate and stabilize this β-CGTase, but to different degrees. The most significant increase (about 20%) in β-cyclodextrin-forming activity was achieved by adding 10-15% PEG 400.

Analysis of the arabinose-5-phosphate isomerase of Bacteroides fragilis provides insight into regulation of single-domain arabinose phosphate isomerases.

Arabinose-5-phosphate isomerases (APIs) catalyze the interconversion of d-ribulose-5-phosphate and D-arabinose-5-phosphate, the first step in the biosynthesis of 3-deoxy-D-manno-octulosonic acid (Kdo), an essential component of the lipopolysaccharide in Gram-negative bacteria. Classical APIs, such as Escherichia coli KdsD, contain a sugar isomerase domain and a tandem cystathionine beta-synthase domain. Despite substantial effort, little is known about structure-function relationships in these APIs.

Arabinose 5-phosphate isomerase as a target for antibacterial design: studies with substrate analogues and inhibitors.

Structural requirements of D-arabinose 5-phosphate isomerase (KdsD, E.C. 5.

A simple assay for 3-deoxy-d-manno-octulosonate cytidylyltransferase and its use as a pathway screen.

This article describes the adaptation of a simple colorimetric assay for inorganic pyrophosphate to the enzyme 3-deoxy-d-manno-octulosonate cytidylyltransferase (CMP-KDO synthetase, KdsB, EC 2.7.7.

A unique arabinose 5-phosphate isomerase found within a genomic island associated with the uropathogenicity of Escherichia coli CFT073.

Previous studies showed that deletion of genes c3405 to c3410 from PAI-metV, a genomic island from Escherichia coli CFT073, results in a strain that fails to compete with wild-type CFT073 after a transurethral cochallenge in mice and is deficient in the ability to independently colonize the mouse kidney. Our analysis of c3405 to c3410 suggests that these genes constitute an operon with a role in the internalization and utilization of an unknown carbohydrate. This operon is not found in E.

Trypanosoma brucei glycogen synthase kinase-3, a target for anti-trypanosomal drug development: a public-private partnership to identify novel leads.

Background: Trypanosoma brucei, the causative agent of Human African Trypanosomiasis (HAT), expresses two proteins with homology to human glycogen synthase kinase 3β (HsGSK-3) designated TbruGSK-3 short and TbruGSK-3 long. TbruGSK-3 short has previously been validated as a potential drug target and since this enzyme has also been pursued as a human drug target, a large number of inhibitors are available for screening against the parasite enzyme. A collaborative industrial/academic partnership facilitated by the World Health Organisation Tropical Diseases Research division (WHO TDR) was initiated to stimulate research aimed at identifying new drugs for treating HAT.

Targeting the non-structural proteins of hepatitis C virus: beyond hepatitis C virus protease and polymerase.

Background: Chronic hepatitis C virus (HCV) infection is a main cause of cirrhosis of the liver and hepatocellular carcinoma. The standard of care is a combination of pegylated interferon with ribavirin, a regimen that has undesirable side effects and is frequently ineffective. Compounds targeting HCV protease and polymerase are in late-stage clinical trials and have been extensively reviewed elsewhere.

Simultaneous screening of multiple bacterial tRNA synthetases using an Escherichia coli S30-based transcription and translation assay.

The search for novel antibiotics to combat the growing threat of resistance has led researchers to screen libraries with coupled transcription and translation systems. In these systems, a bacterial cell lysate supplies the proteins necessary for transcription and translation, a plasmid encoding a reporter protein is added as a template, and a complex mixture of amino acids and cofactors is added to supply building blocks and energy to the assay. Firefly luciferase is typically used as the reporter protein in high-throughput screens because the luminescent signal is strong and, since bacterial lysates contain no luciferase, the background is negligible.

Structural biology approaches to antibacterial drug discovery.

Antibacterial drug discovery has undertaken a major experiment in the 12 years since the first bacterial genomes were sequenced. Genome mining has identified hundreds of potential targets that have been distilled to a relatively small number of broad-spectrum targets ('low-hanging fruit') using the genetics tools of modern microbiology. Prosecuting these targets with high-throughput screens has led to a disappointingly small number of lead series that have mostly evaporated under closer scrutiny.

Synthesis and structure-activity relationship study of potent trypanocidal thio semicarbazone inhibitors of the trypanosomal cysteine protease cruzain.

American trypanosomiasis, or Chagas' disease, is the leading cause of heart disease in Latin America. Currently there is an urgent need to develop antitrypanosomal therapy due to the toxicity of existing agents and emerging drug resistance. A novel series of potent thio semicarbazone small-molecule inhibitors of the Trypanosoma cruzi cysteine protease cruzain have been identified.