Modulation of the function of small GTPases that regulate vesicular trafficking is a strategy employed by several human pathogens. Legionella pneumophila infects lung macrophages and injects a plethora of different proteins into its host cell. Among these is DrrA/SidM, which catalyzes stable adenylylation of Rab1b, a regulator of endoplasmatic reticulum to Golgi trafficking, and thereby alters the function and interactions of this small GTPase. We employed time-resolved FTIR-spectroscopy to monitor the DrrA-catalyzed AMP-transfer to Tyr77 of Rab1b. A transient complex between DrrA, adenylylated Rab1b, and the pyrophosphate byproduct was resolved, allowing us to analyze the interactions at the active site. Combination of isotopic labeling and site-directed mutagenesis allowed us to derive the catalytic mechanism of DrrA from the FTIR difference spectra. DrrA shares crucial residues in the ATP-binding pocket with similar AMP-transferring enzymes such as glutamine synthetase adenylyltransferase or kanamycin nucleotidyltransferase, but provides the complete active site on a single subunit. We determined that Asp112 of DrrA functions as the catalytic base for deprotonation of Tyr77 of Rab1b to enable nucleophilic attack on the ATP. The study provides detailed understanding of the Legionella pneumophila protein DrrA and of AMP-transfer reactions in general.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1021/ja501496d | DOI Listing |
Microorganisms
December 2024
School of Life Sciences, University of Essex, Wivenhoe Park, Colchester, CO4 3SQ, UK.
Multiple human and plant pathogens are dispersed and transmitted as bioaerosols (e.g., , SARS-CoV-2, , , spp.
View Article and Find Full Text PDFAntibiotics (Basel)
November 2024
Laboratory of Microbiology, Nova Medical School, Universidade Nova de Lisboa, 1169-056 Lisboa, Portugal.
Background: species are the causative agent of Legionnaires' disease and, as ubiquitous waterborne bacteria, are prone to antimicrobial resistance gene (ARG) acquisition and dissemination due to the antimicrobial contamination of natural environments. Given the potential health risks associated with ARGs, it is crucial to assess their presence in the population.
Methods: The ARGs and were detected in 348 samples, isolates, and DNA extracts using conventional PCR.
Front Immunol
January 2025
Centro Multidisciplinario de Estudios en Biotecnología, Facultad de Medicina Veterinaria y Zootecnia, Universidad Michoacana de San Nicolás de Hidalgo, Morelia, Mexico.
Pathogenic bacteria trigger complex molecular interactions in hosts that are characterized mainly by an increase in reactive oxygen species (ROS) as well as an inflammation-associated response. To counteract oxidative damage, cells respond through protective mechanisms to promote resistance and avoid tissue damage and infection; among these cellular mechanisms the activation or inhibition of the nuclear factor E2-related factor 2 (Nrf2) is frequently observed. The transcription factor Nrf2 is considered the regulator of several hundred cytoprotective and antioxidant genes.
View Article and Find Full Text PDFMucosal Immunol
December 2024
Department of Infectious Diseases, Respiratory Medicine and Critical Care, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Augustenburger Platz 1, 13353 Berlin, Germany; German center for lung research (DZL), Augustenburger Platz 1, 13353 Berlin, Germany. Electronic address:
Diabetes mellitus is associated with an increased risk of pneumonia, often caused by so-called typical and atypical pathogens including Streptoccocus pneumoniae and Legionella pneumophila, respectively. Here, we employed a variety of mouse models to investigate how diabetes influences pulmonary antibacterial immunity. Following intranasal infection with S.
View Article and Find Full Text PDFAnn Agric Environ Med
December 2024
Collegium Medicum, Jan Kochanowski University, Kielce, Poland.
Introduction And Objective: Water in installations in hospitals and social welfare homes (SWHs) should meet the requirements of the Directive of the European Parliament and of the Council on the quality of water intended for human consumption and national regulations issued on its basis. At present, 60 species of bacteria of the genus Legionella sp. are known (of which 30 are considered as pathogenic for humans), and more than 80 serologic groups.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!