Crystal structure of UDP-N-acetylglucosamine enolpyruvyltransferase, the target of the antibiotic fosfomycin

Abstract

The present structure reflects the open conformation of the enzyme which is probably stabilized through two residues, a lysine and an arginine, located in the cleft between the domains. Binding of the negatively charged UDPGlcNAc to these residues could neutralize the repulsive force between the two domains, thereby allowing the movement of a catalytically active cysteine residue towards the cleft.

Phosphate Analogues as Probes of the Catalytic Mechanisms of MurA and AroA, Two Carboxyvinyl Transferases

“…They concluded that PEP inside the catalytic center was protonated and the enzyme stabilized an oxacarbenium ion upon binding with UDP-GicNAc. The substrate-induced conformational change was later demonstrated in both crystal structure (7,25,26) and fluorescence experiments (21).…”

“…The reaction mechanisms of both MurA and AroA have been studied intensively with pre-steady state experiments (11,14,15), site directed mutagenesis (11), substrate analogues (16)(17)(18), x-ray crystallography (7,19,20), fluorescence titration (21) and NMR experiments (6,22). Their mechanisms are similar in several aspects.…”

“…MurA and AroA are homologous, sharing the same overall three-dimensional architecture: two globular inside-out a/~-barrel domains connected by a two-stranded hinge (7). Both undergo substrate-induced conformational changes that form the active center for catalysis, and which can be monitored by fluorescence changes (5,8).…”

Functional Consequence of Covalent Reaction of Phosphoenolpyruvate with UDP-N-acetylglucosamine 1-Carboxyvinyltransferase (MurA)

“…However, the discovery that Cys-115 could be replaced by an aspartate without loss of activity (a mutation found in some bacteria including Mycobacteria) led to the conclusion that Cys-115 functions as a general acid-base catalyst and not as a nucleophile in the reaction with PEP (10). Cys-115 is a member of a 10-residue loop in the N-terminal globular domain that undergoes drastic conformational changes upon binding of UNAG by approaching the interdomain cleft and positioning the Cys-115 side chain into the PEP binding site (11)(12)(13)(14)(15). Cys-115 has received considerable attention as the target of covalent modification by fosfomycin (12) and other electrophilic natural products such as terreic acid (16) and cnicin (17).…”

UDP-N-acetilglicosamina enolpiruvil transferase: determinação dos estados de protonação de resíduos de aminoácidos do sítio ativo pelo método PM6

“…A enzima MurA catalisa o primeiro passo na biossíntese do heteropolímero peptideoglicano, o principal elemento estrutural formador da parede celular das bactérias. [2][3][4] No processo catalisado pela MurA, ocorre a reação entre o UDP-Nacetilglicosamina (UNAG) e o fosfoenolpiruvato (PEP), formando os produtos enolpiruvil-UDP-N-acetilglicosamina (EP-UNAG) e fosfato inorgânico. 2 A enzima AroA catalisa a sexta etapa da biossíntese do corismato, que é um precursor para a biossíntese de compostos aromáticos em plantas, fungos, bactérias e algas.…”