Novel Thienopyrimidine Inhibitors of -Myristoyltransferase with On-Target Activity in Intracellular Amastigotes.

The leishmaniases, caused by species of protozoan parasites, are neglected tropical diseases with millions of cases worldwide. Current therapeutic approaches are limited by toxicity, resistance, and cost. -Myristoyltransferase (NMT), an enzyme ubiquitous and essential in all eukaryotes, has been validated via genetic and pharmacological methods as a promising anti-leishmanial target.

Water Networks Can Determine the Affinity of Ligand Binding to Proteins.

Solvent organization is a key but underexploited contributor to the thermodynamics of protein-ligand recognition, with implications for ligand discovery, drug resistance, and protein engineering. Here, we explore the contribution of solvent to ligand binding in the virulence protein SiaP. By introducing a single mutation without direct ligand contacts, we observed a >1000-fold change in sialic acid binding affinity.

Structure-guided optimization of quinoline inhibitors of -myristoyltransferase.

The parasite is the most widely distributed cause of recurring malaria. -Myristoyltransferase (NMT), an enzyme that catalyses the covalent attachment of myristate to the N-terminal glycine of substrate proteins, has been described as a potential target for the treatment of this disease. Herein, we report the synthesis and the structure-guided optimization of a series of quinolines with balanced activity against both and -myristoyltransferase (NMT).

Three-dimensional structures of two heavily N-glycosylated Aspergillus sp. family GH3 β-D-glucosidases.

The industrial conversion of cellulosic plant biomass into useful products such as biofuels is a major societal goal. These technologies harness diverse plant degrading enzymes, classical exo- and endo-acting cellulases and, increasingly, cellulose-active lytic polysaccharide monooxygenases, to deconstruct the recalcitrant β-D-linked polysaccharide. A major drawback with this process is that the exo-acting cellobiohydrolases suffer from severe inhibition from their cellobiose product.

Structure-based design of potent and selective Leishmania N-myristoyltransferase inhibitors.

Inhibitors of Leishmania N-myristoyltransferase (NMT), a potential target for the treatment of leishmaniasis, obtained from a high-throughput screen, were resynthesized to validate activity. Crystal structures bound to Leishmania major NMT were obtained, and the active diastereoisomer of one of the inhibitors was identified. On the basis of structural insights, enzyme inhibition was increased 40-fold through hybridization of two distinct binding modes, resulting in novel, highly potent Leishmania donovani NMT inhibitors with good selectivity over the human enzyme.

Peptidomimetic inhibitors of N-myristoyltransferase from human malaria and leishmaniasis parasites.

N-Myristoyltransferase (NMT) has been shown to be essential in Leishmania and subsequently validated as a drug target in Plasmodium. Herein, we discuss the use of antifungal NMT inhibitors as a basis for inhibitor development resulting in the first sub-micromolar peptidomimetic inhibitors of Plasmodium and Leishmania NMTs. High-resolution structures of these inhibitors with Plasmodium and Leishmania NMTs permit a comparative analysis of binding modes, and provide the first crystal structure evidence for a ternary NMT-Coenzyme A/myristoylated peptide product complex.

Diverse modes of binding in structures of Leishmania major N-myristoyltransferase with selective inhibitors.

The leishmaniases are a spectrum of global diseases of poverty associated with immune dysfunction and are the cause of high morbidity. Despite the long history of these diseases, no effective vaccine is available and the currently used drugs are variously compromised by moderate efficacy, complex side effects and the emergence of resistance. It is therefore widely accepted that new therapies are needed.

Degradation of phytate by the 6-phytase from Hafnia alvei: a combined structural and solution study.

Phytases hydrolyse phytate (myo-inositol hexakisphosphate), the principal form of phosphate stored in plant seeds to produce phosphate and lower phosphorylated myo-inositols. They are used extensively in the feed industry, and have been characterised biochemically and structurally with a number of structures in the PDB. They are divided into four distinct families: histidine acid phosphatases (HAP), β-propeller phytases, cysteine phosphatases and purple acid phosphatases and also split into three enzyme classes, the 3-, 5- and 6-phytases, depending on the position of the first phosphate in the inositol ring to be removed.

The crystallization and structural analysis of cellulases (and other glycoside hydrolases): strategies and tactics.

The three-dimensional (3-D) structures of cellulases, and other glycoside hydrolases, are a central feature of research in carbohydrate chemistry and biochemistry. 3-D structure is used to inform protein engineering campaigns, both academic and industrial, which are typically used to improve the stability or activity of an enzyme. Examples of classical protein engineering goals include higher thermal stability, reduced metal-ion dependency, detergent and protease resistance, decreased product inhibition, and altered specificity.

Design, synthesis, and evaluation of 5'-diphenyl nucleoside analogues as inhibitors of the Plasmodium falciparum dUTPase.

Deoxyuridine 5'-triphosphate nucleotidohydrolase (dUTPase) is a potential drug target for malaria. We previously reported some 5'-tritylated deoxyuridine analogues (both cyclic and acyclic) as selective inhibitors of the Plasmodium falciparum dUTPase. Modelling studies indicated that it might be possible to replace the trityl group with a diphenyl moiety, as two of the phenyl groups are buried, whereas the third is exposed to solvent.

Structure and activity of Paenibacillus polymyxa xyloglucanase from glycoside hydrolase family 44.

The enzymatic degradation of plant polysaccharides is emerging as one of the key environmental goals of the early 21st century, impacting on many processes in the textile and detergent industries as well as biomass conversion to biofuels. One of the well known problems with the use of nonstarch (nonfood)-based substrates such as the plant cell wall is that the cellulose fibers are embedded in a network of diverse polysaccharides, including xyloglucan, that renders access difficult. There is therefore increasing interest in the "accessory enzymes," including xyloglucanases, that may aid biomass degradation through removal of "hemicellulose" polysaccharides.

β-Branched acyclic nucleoside analogues as inhibitors of Plasmodium falciparum dUTPase.

We report a series of β-branched acyclic tritylated deoxyuridine analogues as inhibitors of Plasmodium falciparum deoxyuridine-5'-triphosphate nucleotidohydrolase (PfdUTPase), an enzyme involved in nucleotide metabolism that acts as first line of defence against uracil incorporation into DNA. Compounds were assayed against both PfdUTPase and intact parasites showing a correlation between enzyme inhibition and cellular assays. β-Branched acyclic uridine analogues described here showed equal or slightly better potency and selectivity compared with previously reported analogues.

Circular permutation provides an evolutionary link between two families of calcium-dependent carbohydrate binding modules.

The microbial deconstruction of the plant cell wall is a critical biological process, which also provides important substrates for environmentally sustainable industries. Enzymes that hydrolyze the plant cell wall generally contain non-catalytic carbohydrate binding modules (CBMs) that contribute to plant cell wall degradation. Here we report the biochemical properties and crystal structure of a family of CBMs (CBM60) that are located in xylanases.

Casuarine-6-O-alpha-D-glucoside and its analogues are tight binding inhibitors of insect and bacterial trehalases.

Two novel casuarine-6-alpha-D-glucoside analogues, as well as the parent compound, were synthesized and tested as inhibitors towards Chironomus riparius, mammalian pig kidney and Escherichia coli trehalases. Their potent and selective activity is promising for the development of new insecticides.

Understanding how diverse beta-mannanases recognize heterogeneous substrates.

The mechanism by which polysaccharide-hydrolyzing enzymes manifest specificity toward heterogeneous substrates, in which the sequence of sugars is variable, is unclear. An excellent example of such heterogeneity is provided by the plant structural polysaccharide glucomannan, which comprises a backbone of beta-1,4-linked glucose and mannose units. beta-Mannanases, located in glycoside hydrolase (GH) families 5 and 26, hydrolyze glucomannan by cleaving the glycosidic bond of mannosides at the -1 subsite.

Crystallographic and solution studies of N-lithocholyl insulin: a new generation of prolonged-acting human insulins.

The addition of specific bulky hydrophobic groups to the insulin molecule provides it with affinity for circulating serum albumin and enables it to form soluble macromolecular complexes at the site of subcutaneous injection, thereby securing slow absorption of the insulin analogue into the blood stream and prolonging its half-life once there. N-Lithocholic acid acylated insulin [Lys(B29)-lithocholyl des-(B30) human insulin] has been crystallized and the structure determined by X-ray crystallography at 1.6 A resolution to explore the molecular basis of its assembly.

Cellvibrio japonicus alpha-L-arabinanase 43A has a novel five-blade beta-propeller fold.

Cellvibrio japonicus arabinanase Arb43A hydrolyzes the alpha-1,5-linked L-arabinofuranoside backbone of plant cell wall arabinans. The three-dimensional structure of Arb43A, determined at 1.9 A resolution, reveals a five-bladed beta-propeller fold.