Referencia

JACS; 2017 May 8; 139(20):6795-6798. DOI: 10.1021/jacs.7b01626 Portada JACS

Autores

Iván Acebrón, Kiran V. Mahasenan, Stefania de Benedetti, Mijoon Lee, Cecilia Artola Recolons, Dusan Hesek, Huan Wang, Juan Antonio Hermoso y Shahriar Mobashery

Resumen

The N-acetylglucosaminidase NagZ of Pseudomonas aeruginosa catalyzes the first cytoplasmic step in recycling of muropeptides, cell-wall-derived natural products. This reaction regulates gene expression for the β-lactam resistance enzyme, β-lactamase. The enzyme catalyzes hydrolysis of N-acetyl-β-d-glucosamine-(1→4)-1,6-anhydro-N-acetyl-β-d-muramyl-peptide (1) to N-acetyl-β-d-glucosamine (2) and 1,6-anhydro-N-acetyl-β-d-muramyl-peptide (3). The structural and functional aspects of catalysis by NagZ were investigated by a total of seven X-ray structures, three computational models based on the X-ray structures, molecular-dynamics simulations and mutagenesis. The structural insights came from the unbound state and complexes of NagZ with the substrate, products and a mimetic of the transient oxocarbenium species, which were prepared by synthesis. The mechanism involves a histidine as acid/base catalyst, which is unique for glycosidases. The turnover process utilizes covalent modification of D244, requiring two transition-state species and is regulated by coordination with a zinc ion. The analysis provides a seamless continuum for the catalytic cycle, incorporating large motions by four loops that surround the active site.

Descripción

Desvelado el mecanismo catalítico de NagZ, una enzima clave en la resistencia a antibióticos de Pseudomonas aeruginosa

NagZ de Pseudomonas aeruginosa cataliza el primer paso del reciclaje de los muropéptidos (fragmentos naturales de la pared bacteriana) en el citoplasma y regula la expresión de la -lactamasa, la enzima clave en la resistencia a antibióticos -lactámicos. Los aspectos estructurales y funcionales de la catálisis de NagZ se investigaron mediante un total de siete estructuras cristalinas, dinámica molecular y por mutagénesis dirigida. Las estructuras muestran cambios estructurales profundos requeridos para la activación y descubren al Zn como un regulador de su actividad. El trabajo proporciona una imagen de todos los pasos del ciclo catalítico de NagZ en este importante patógeno humano.

 

 

fotogrupoagosto

 

REFERENCIA DEL GRUPO INVESTIGADOR

La investigación en el grupo de Juan A. Hermoso se centra en la caracterización estructural de los mecanismos de virulencia y patogénesis bacteriana y en el modo de superarlos. Nos hemos focalizado en la Biología Estructural de las proteínas de la superficie bacteriana involucradas en funciones clave, tales como unión del patógeno al hospedador humano, resistencia a antibióticos, división o los procesos de remodelado de la pared bacteriana, cruciales en el desarrollo de la enfermedad infecciosa (http://www.xtal.iqfr.csic.es/grupo/xjuan/). Iván Acebrón ha desarrollado este trabajo como postdoctoral en el grupo de J.A. Hermoso y se encuentra actualmente en el grupo de D. Lietha en el CNIO.X

Ver más de este artículo aquí.

¿Acabas de publicar un artículo interesante?

Manda la referencia a través de nuestro formulario.  Límite de edad 32 años. Los artículos seleccionados serán destacados como artículos del mes y participarán en el Premio al mejor artículo de jóvenes de la SEBBM, que se entregará en el congreso de la SEBBM (inscripción y alojamiento gratuitos).

Otros "Artículos del mes"

The structure of a polygamous repressor reveals how phage-inducible chromosomal islands spread in nature

01-11-2019

Stl is a master repressor encoded by Staphylococcus aureus pathogenicity islands (SaPIs) that maintains integration of these elements in the bacterial chromosome. After infection or induction of a resident helper...

Leer más

Self-Assembling ELR-Based Nanoparticles as Smart Drug-Delivery Systems Modulating Cellular Growth via Akt

01-10-2019

This work investigates the physicochemical properties and in vitro accuracy of a genetically engineered drug delivery system based on elastin-like block recombinamers. The DNA recombinant technics allowed us to create...

Leer más

Structure–Function of MamC Loop and Its Effect on the *in Vitro* Precipitation of Biomimetic Magnetite Nanoparticles

01-09-2019

MamC, an integral protein of the magnetosome membrane, has recently been proposed as a strong candidate to produce biomimetic (magnetosome-like) magnetite nanoparticles that could be used as an alternative to...

Leer más

Sticholysin, Sphingomyelin, and Cholesterol: A Closer Look at a Tripartite Interaction

01-08-2019

Actinoporins are a group of soluble toxic proteins that bind to membranes containing sphingomyelin (SM) and oli- gomerize to form pores. Sticholysin II (StnII) is a member of the actinoporin...

Leer más

Astrocytic mitochondrial ROS modulate brain metabolism and mouse behaviour

01-07-2019

To satisfy its high energetic demand, the brain depends on the metabolic cooperation of various cell types. For example, astrocytic-derived lactate sustains memory consolidation by serving both as an oxidizable...

Leer más

Glucose restriction promotes osteocyte specification by activating a PGC-1α-dependent transcriptional program

03-06-2019

Osteocytes, the most abundant of bone cells, differentiate while they remain buried within the bone matrix. This encasement limits their access to nutrients and likely affects their differentiation, a process...

Leer más

ParB dynamics and the critical role of the CTD in DNA condensation unveiled by combined force-fluorescence measurements

01-05-2019

/Bacillus subtilis/ ParB forms multimeric networks involving non-specific DNA binding leading to DNA condensation. Previously, we found that an excess of the free C-terminal domain (CTD) of ParB impeded DNA...

Leer más

Therapeutic targeting of HER2-CB2R heteromers in HER2-positive breast cancer

01-04-2019

Although human epidermal growth factor receptor 2 (HER2)-targeted therapies have dramatically improved the clinical outcome of HER2-positive breast cancer patients, innate and acquired resistance remains an important clinical challenge. New...

Leer más

p73 regulates ependymal planar cell polarity by modulating actin and microtubule cytoskeleton

01-03-2019

Planar cell polarity (PCP) and intercellular junctional complexes establish tissue structure and coordinated behaviors across epithelial sheets. In multiciliated ependymal cells, rotational and translational PCP coordinate cilia beating and direct...

Leer más

β‐RA reduces DMQ/CoQ ratio and rescues the encephalopathic phenotype in Coq9R239X mice

01-02-2019

Coenzyme Q (CoQ) deficiency has been associated with primary defects in the CoQ biosynthetic pathway or to secondary events. In some cases, the exogenous CoQ supplementation has limited efficacy. In...

Leer más

Socios Protectores