Inhibition of chorismate-utilising enzymes by 2-amino-4-carboxypyridine and 4-carboxypyridone and 5-carboxypyridone analogues.

Several 2-amino-4-carboxypyridine, 4- and 5-carboxypyridone-based compounds were prepared and tested against three members of the chorismate-utilising enzyme family, anthranilate synthase, isochorismate synthase and salicylate synthase. Most compounds exhibited low micromolar inhibition of these three enzymes. The most potent inhibitor was a 4-carboxypyridone analogue bearing a lactate side chain on the pyridyl nitrogen which exhibited inhibition constants of 5, 91 and 54 muM against anthranilate synthase, isochorismate synthase and salicylate synthase respectively.

Crystal structure of Escherichia coli enterobactin-specific isochorismate synthase (EntC) bound to its reaction product isochorismate: implications for the enzyme mechanism and differential activity of chorismate-utilizing enzymes.

EntC, one of two isochorismate synthases in Escherichia coli, is specific to the biosynthesis of the siderophore enterobactin. Here, we report the crystal structure of EntC in complex with isochorismate and Mg(2+)at 2.3 A resolution, the first structure of a chorismate-utilizing enzyme with a non-aromatic reaction product.

Long-lasting enfuvirtide carrier pentasaccharide conjugates with potent anti-human immunodeficiency virus type 1 activity.

Enfuvirtide (also known as Fuzeon, T-20, or DP-178) is an antiretroviral fusion inhibitor which prevents human immunodeficiency virus type 1 (HIV-1) from entering host cells. This linear 36-mer synthetic peptide is indicated, in combination with other antiretroviral agents, for the treatment of HIV-1-infected individuals and AIDS patients with multidrug-resistant HIV infections. Although enfuvirtide is an efficient anti-HIV-1 drug, its clinical use is limited by a short plasma half-life, i.

Synthesis and evaluation of 2,5-dihydrochorismate analogues as inhibitors of the chorismate-utilising enzymes.

A library of 2,5-dihydrochorismate analogues were designed as inhibitors of the chorismate-utilising enzymes including anthranilate synthase, isochorismate synthase, salicylate synthase and 4-amino-4-deoxychorismate synthase. The inhibitors were synthesised in seven or eight steps from shikimic acid, sourced from star anise. The compounds exhibited moderate but differential inhibition against the four chorismate-utilising enzymes.

Rational design, synthesis, and evaluation of nanomolar type II dehydroquinase inhibitors.

The in silico design, synthesis, and biological evaluation of ten potent type II dehydroquinase inhibitors are described. These compounds contain an anhydroquinate core, incorporated as a mimic of the enolate reaction intermediate. This substructure is attached by a variety of linking units to a terminal phenyl group that binds in an adjacent pocket.

Nanomolar inhibition of type II dehydroquinase based on the enolate reaction mechanism.

We describe the rational design of a novel, highly potent inhibitor of type II dehydroquinase, the dicarboxylate 6. The incorporation of a carboxylate at the 3-position mimics the putative enolate intermediate in the reaction mechanism, and allows a potential electrostatic binding interaction with the arginine on the active site flap. This results in a 1000-fold increase in potency, making the dicarboxylate 6 the most potent inhibitor of type II dehydroquinase reported to date, with a high ligand efficiency of -0.

Crystal structures of Yersinia enterocolitica salicylate synthase and its complex with the reaction products salicylate and pyruvate.

The salicylate synthase, Irp9, from Yersinia enterocolitica is involved in the biosynthesis of the siderophore yersiniabactin. It is a bifunctional enzyme that forms salicylate and pyruvate from chorismate and water via the intermediate isochorismate. Here we report the first crystal structure of Irp9 and also of its complex with the reaction products salicylate and pyruvate at 1.

Mechanism of alpha-oxoamine synthases: identification of the intermediate Claisen product in the 8-amino-7-oxononanoate synthase reaction.

The reactive beta-ketoacid pyridoxal-5'-phosphate aldimine formed in the condensation step of the 8-amino-7-oxononanoate synthase reaction was 'trapped' in the enzyme-bound form by carrying out the reaction with l-alanine methyl ester and pimeloyl-CoA affording the more stable methyl ester of the putative intermediate, the characterisation of which provides the first definitive evidence for a beta-ketoacid intermediate in an alpha-oxamine synthase mechanism.

Salicylate biosynthesis: overexpression, purification, and characterization of Irp9, a bifunctional salicylate synthase from Yersinia enterocolitica.

In some bacteria, salicylate is synthesized using the enzymes isochorismate synthase and isochorismate pyruvate lyase. In contrast, gene inactivation and complementation experiments with Yersinia enterocolitica suggest the synthesis of salicylate in the biosynthesis of the siderophore yersiniabactin involves a single protein, Irp9, which converts chorismate directly into salicylate. In the present study, Irp9 was for the first time heterologously expressed in Escherichia coli as a hexahistidine fusion protein, purified to near homogeneity, and characterized biochemically.

Inhibition studies on salicylate synthase.

Analogues of chorismate and isochorismate were designed and tested as potential inhibitors in the first inhibition study against a salicylate synthase.