Structural Basis for Rab1 De-AMPylation by the Legionella pneumophila Effector SidD

PLoS Pathogens

Matthias P. Machner¹  Jacqueline Brady¹  M. Ramona Neunuebel¹  Yang Chen¹  Juan Fernández-Recio²  Chiara Pallara²  Aitor Hierro³  Adriana L. Rojas³  Igor Tascón³  Lisa N. Kinch⁴ 

[1] Cell Biology and Metabolism Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, United States of America;Joint BSC-IRB research program in Computational Biology, Barcelona Supercomputing Center, Barcelona, Spain;Structural Biology Unit, CIC bioGUNE, Bizkaia Technology Park, Derio, Spain;University of Texas Southwestern Medical Center, Dallas, Texas, United States of America

关键词: Phosphatases;    Legionella pneumophila;    Crystal structure;    Host cells;    Guanosine triphosphatase;    Molecular dynamics;    Phosphates;    Free energy;   

DOI  :  10.1371/journal.ppat.1003382

学科分类：生物科学（综合）

来源: Public Library of Science

【 摘 要 】

The covalent attachment of adenosine monophosphate (AMP) to proteins, a process called AMPylation (adenylylation), has recently emerged as a novel theme in microbial pathogenesis. Although several AMPylating enzymes have been characterized, the only known virulence protein with de-AMPylation activity is SidD from the human pathogen Legionella pneumophila. SidD de-AMPylates mammalian Rab1, a small GTPase involved in secretory vesicle transport, thereby targeting the host protein for inactivation. The molecular mechanisms underlying Rab1 recognition and de-AMPylation by SidD are unclear. Here, we report the crystal structure of the catalytic region of SidD at 1.6 Å resolution. The structure reveals a phosphatase-like fold with additional structural elements not present in generic PP2C-type phosphatases. The catalytic pocket contains a binuclear metal-binding site characteristic of hydrolytic metalloenzymes, with strong dependency on magnesium ions. Subsequent docking and molecular dynamics simulations between SidD and Rab1 revealed the interface contacts and the energetic contribution of key residues to the interaction. In conjunction with an extensive structure-based mutational analysis, we provide in vivo and in vitro evidence for a remarkable adaptation of SidD to its host cell target Rab1 which explains how this effector confers specificity to the reaction it catalyses.

【 授权许可】

CC BY