Reaction products and the X-ray structure of AmpDh2, a virulence determinant of Pseudomonas aeruginosa

4 pags, 4 figs. -- Supporting Information is available at the Publisher web.The zinc protease AmpDh2 is a virulence determinant of Pseudomonas aeruginosa, a problematic human pathogen. The mechanism of how the protease manifests virulence is not known, but it is known that it turns over the bacterial cell wall. The reaction of AmpDh2 with the cell wall was investigated, and nine distinct turnover products were characterized by LC/MS/MS. The enzyme turns over both the cross-linked and noncross-linked cell wall. Three high-resolution X-ray structures, the apo enzyme and two complexes with turnover products, were solved. The X-ray structures show how the dimeric protein interacts with the inner leaflet of the bacterial outer membrane and that the two monomers provide a more expansive surface for recognition of the cell wall. This binding surface can accommodate the 3D solution structure of the cross-linked cell wall. © 2013 American Chemical Society.This work was supported by a grant from the NIH (GM61629) and by grants BFU2011-25326 (the Spanish Ministry of Economy and Competitiveness) and S2010/BMD-2457 (the Government of Community of Madrid). The Mass Spectrometry & Proteomics Facility of the University of Notre Dame is supported by grant CHE0741793 from the NSF

How Allosteric Control of Staphylococcus aureus Penicillin-Binding Protein 2a Enables Methicillin-Resistance and Physiological Function

The expression of penicillin binding protein 2a (PBP2a) is the basis for the broad clinical resistance to the β-lactam antibiotics by methicillin-resistant Staphylococcus aureus (MRSA). The highmolecular mass penicillin binding proteins of bacteria catalyze in separate domains the transglycosylase and transpeptidase activities required for the biosynthesis of the peptidoglycan polymer that comprises the bacterial cell wall. In bacteria susceptible to β-lactam antibiotics, the transpeptidase activity of their penicillin binding proteins (PBPs) is lost as a result of irreversible acylation of an active site serine by the β-lactam antibiotics. In contrast, the PBP2a of MRSA is resistant to β-lactam acylation and successfully catalyzes the DD-transpeptidation reaction necessary to complete the cell wall. The inability to contain MRSA infection with β-lactam antibiotics is a continuing public health concern. We report herein the identification of an allosteric binding domain - a remarkable 60 Å distant from the DD-transpeptidase active site - discovered by crystallographic analysis of a soluble construct of PBP2a. When this allosteric site is occupied, a multiresidue conformational change culminates in the opening of the active site to permit substrate entry. This same crystallographic analysis also reveals the identity of three allosteric ligands: muramic acid (a saccharide component of the peptidoglycan), the cell wall peptidoglycan, and ceftaroline, a recently approved anti-MRSA β-lactam antibiotic. The ability of an anti-MRSA β-lactam antibiotic to stimulate allosteric opening of the active site, thus predisposing PBP2a to inactivation by a second β-lactam molecule, opens an unprecedented realm for β-lactam antibiotic structure-based design.Fil: Otero, Lisandro Horacio. Consejo Superior de Investigaciones Científicas. Instituto de Química Física; España. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Biología Molecular y Celular de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Biología Molecular y Celular de Rosario; ArgentinaFil: Rojas Altuve, Alzoray. Consejo Superior de Investigaciones Científicas. Instituto de Química Física; EspañaFil: Llarrull, Leticia Irene. University of Notre Dame; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Biología Molecular y Celular de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Biología Molecular y Celular de Rosario; ArgentinaFil: Carrasco López, Cesar. Consejo Superior de Investigaciones Científicas. Instituto de Química Física; EspañaFil: Kumarasiri, Malika. University of Notre Dame; Estados UnidosFil: Lastochkin, Elena. University of Notre Dame; Estados UnidosFil: Fishovitz, Jennifer. University of Notre Dame; Estados UnidosFil: Dawley, Matthew. University of Notre Dame; Estados UnidosFil: Hesek, Dusan. University of Notre Dame; Estados UnidosFil: Lee, Mijoon. University of Notre Dame; Estados UnidosFil: Johnson, Jarrod W.. University of Notre Dame; Estados UnidosFil: Fisher, Jed F.. University of Notre Dame; Estados UnidosFil: Chang, Mayland. University of Notre Dame; Estados UnidosFil: Mobashery, Shahriar. University of Notre Dame; Estados UnidosFil: Hermoso, Juan A.. Consejo Superior de Investigaciones Científicas. Instituto de Química Física; Españ

Structure-Activity Relationship for the Oxadiazole Class of Antibacterials

A structure-activity relationship (SAR) for the oxadiazole class of antibacterials was evaluated by syntheses of 72 analogs and determination of the minimal-inhibitory concentrations (MICs) against the ESKAPE panel of bacteria. Selected compounds were further evaluated for in vitro toxicity, plasma protein binding, pharmacokinetics (PK), and a mouse model of methicillin-resistant Staphylococcus aureus (MRSA) infection. Oxadiazole 72c shows potent in vitro antibacterial activity, exhibits low clearance, a high volume of distribution, and 41% oral bioavailability, and shows efficacy in mouse models of MRSA infection.Fil: Boudreau, Marc A.. University of Notre Dame; Estados UnidosFil: Ding, Derong. University of Notre Dame; Estados UnidosFil: Meisel, Jayda E.. University of Notre Dame; Estados UnidosFil: Janardhanan, Jeshina. University of Notre Dame; Estados UnidosFil: Spink, Edward. University of Notre Dame; Estados UnidosFil: Peng, Zhihong. University of Notre Dame; Estados UnidosFil: Qian, Yuanyuan. University of Notre Dame; Estados UnidosFil: Yamaguchi, Takao. University of Notre Dame; Estados UnidosFil: Testero, Sebastian Andres. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Química Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Química Rosario; Argentina. University of Notre Dame; Estados UnidosFil: O'Daniel, Peter I.. University of Notre Dame; Estados UnidosFil: Leemans, Erika. University of Notre Dame; Estados UnidosFil: Lastochkin, Elena. University of Notre Dame; Estados UnidosFil: Song, Wei. University of Notre Dame; Estados UnidosFil: Schroeder, Valerie A.. University of Notre Dame; Estados UnidosFil: Wolter, William R.. University of Notre Dame; Estados UnidosFil: Suckow, Mark A.. University of Notre Dame; Estados UnidosFil: Mobashery, Shahriar. University of Notre Dame; Estados UnidosFil: Chang, Mayland. University of Notre Dame; Estados Unido

Structure-Activity Relationship for the Oxadiazole Class of Antibiotics

The structure-activity relationship (SAR) for the newly discovered oxadiazole class of antibiotics is described with evaluation of 120 derivatives of the lead structure. This class of antibiotics was discovered by in silico docking and scoring against the crystal structure of a penicillin-binding protein. They impair cell-wall biosynthesis and exhibit activities against the Gram-positive bacterium Staphylococcus aureus, including methicillin-resistant S. aureus (MRSA) and vancomycin-resistant and linezolid-resistant S. aureus. 5-(1H-Indol-5-yl)-3-(4-(4-(trifluoromethyl)phenoxy)phenyl)-1,2,4-oxadiazole (antibiotic 75b) was efficacious in a mouse model of MRSA infection, exhibiting a long half-life, a high volume of distribution, and low clearance. This antibiotic is bactericidal and is orally bioavailable in mice. This class of antibiotics holds great promise in recourse against infections by MRSA.Fil: Spink, Edward. University of Notre Dame-Indiana; Estados UnidosFil: Ding, Derong. University of Notre Dame-Indiana; Estados UnidosFil: Peng, Zhihong. University of Notre Dame-Indiana; Estados UnidosFil: Boudreau, Marc A.. University of Notre Dame-Indiana; Estados UnidosFil: Leemans, Erika. University of Notre Dame-Indiana; Estados UnidosFil: Lastochkin, Elena. University of Notre Dame-Indiana; Estados UnidosFil: Song, Wei. University of Notre Dame-Indiana; Estados UnidosFil: Lichtenwalter, Katerina. University of Notre Dame-Indiana; Estados UnidosFil: O’Daniel, Peter I.. University of Notre Dame-Indiana; Estados UnidosFil: Testero, Sebastian Andres. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Química Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Química Rosario; Argentina. University of Notre Dame-Indiana; Estados UnidosFil: Pi, Hualiang. University of Notre Dame-Indiana; Estados UnidosFil: Schroeder, Valerie A.. University of Notre Dame-Indiana; Estados UnidosFil: Wolter, William R.. University of Notre Dame-Indiana; Estados UnidosFil: Antunes, Nuno T.. University of Notre Dame-Indiana; Estados UnidosFil: Suckow, Mark A.. University of Notre Dame-Indiana; Estados UnidosFil: Vakulenko, Sergei. University of Notre Dame-Indiana; Estados UnidosFil: Chang, Mayland. University of Notre Dame-Indiana; Estados UnidosFil: Mobashery, Shahriar. University of Notre Dame-Indiana; Estados Unido

Crystallization and preliminary X-ray diffraction analysis of the lytic transglycosylase MltE from Escherichia coli

3 pags, 2 figs, 1 tabMltE from Escherichia coli (193 amino acids, 21 380 Da) is a lytic trans-glycosylase that initiates the first step of cell-wall recycling. This enzyme is responsible for the cleavage of the cell-wall peptidoglycan at the Β-1,4-glycosidic bond between the N-acetylglucosamine and N-acetylmuramic acid units. At the end this reaction generates a disaccharide that is internalized and initiates the recycling process. To obtain insights into the biological functions of MltE, crystallization trials were performed and crystals of MltE protein that were suitable for X-ray diffraction analysis were obtained. The MltE protein of E. coli was crystallized using the hanging-drop vapour-diffusion method at 291 K. Crystals grew from a mixture consisting of 28% polyethylene glycol 4000, 0.1 M Tris pH 8.4 and 0.2 M magnesium chloride. Further optimization was performed using the microbatch technique. Single crystals were obtained that belonged to the orthorhombic space group C2221, with unit-cell parameters a = 123.32, b = 183.93, c = 35.29 Å, and diffracted to a resolution of 2.1 Å. © 2011 International Union of Crystallography. All rights reserved.This work was supported by grants from the Spanish Ministry of Science and Technology (BFU2008-01711 and the Factoría de Cristalización from CONSOLIDER-INGENIO 2010) and the COMBACT program (S-BIO-0260/2006). The work in the USA was supported by the National Institutes of Health. CA-R is a fellow of the Spanish Ministry of Education and Science (BFU2008-01711/BMC). LIL is a Pew Latin American Fellow in the Biomedical Sciences supported by The Pew Charitable Trusts. The opinions expressed are those of the authors and do not necessarily reflect the views of The Pew Charitable Trusts

High-resolution crystal structure of MltE, an outer membrane-anchored endolytic peptidoglycan lytic transglycosylase from Escherichia coli

El pdf del artículo es el manuscrito de autor (PMID:21341761).The crystal structure of the first endolytic peptidoglycan lytic transglycosylase MltE from Escherichia coli is reported here. The degradative activity of this enzyme initiates the process of cell wall recycling, which is an integral event in the existence of bacteria. The structure sheds light on how MltE recognizes its substrate, the cell wall peptidoglycan. It also explains the ability of this endolytic enzyme to cleave in the middle of the peptidoglycan chains. Furthermore, the structure reveals how the enzyme is sequestered on the inner leaflet of the outer membrane. © 2011 American Chemical Society.Este trabajo fue finanaciado por las concesiones bfu2008-01711 y eu-cp223111.Peer Reviewe

Reactions of All Escherichia coli Lytic Transglycosylases with Bacterial Cell Wall

The reactions of all seven Escherichia coli lytic transglycosylases with purified bacterial sacculus are characterized in a quantitative manner. These reactions, which initiate recycling of the bacterial cell wall, exhibit significant redundancy in the activities of these enzymes along with some complementarity. These discoveries underscore the importance of the functions of these enzymes for recycling of the cell wall.Fil: Lee, Mijoon. University Of Notre Dame-indiana; Estados UnidosFil: Hesek, Dusan. University Of Notre Dame-indiana; Estados UnidosFil: Llarrull, Leticia Irene. University Of Notre Dame-indiana; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Biología Molecular y Celular de Rosario; ArgentinaFil: Lastochkin, Elena. University Of Notre Dame-indiana; Estados UnidosFil: Pi, Hualiang. University Of Notre Dame-indiana; Estados UnidosFil: Boggess, Bill. University Of Notre Dame-indiana; Estados UnidosFil: Mobashery, Shahriar. University Of Notre Dame-indiana; Estados Unido