title: Structure-function relations in the NTPase domain of the antiviral tRNA ribotoxin Escherichia coli PrrC.
abstract: Breakage of tRNA by Escherichia coli anticodon nuclease PrrC (EcoPrrC) underlies a host antiviral response to phage T4 infection. Expression of EcoPrrC is cytocidal in yeast, signifying that PrrC ribotoxicity crosses phylogenetic domain boundaries. EcoPrrC consists of an N-terminal NTPase module that resembles ABC transporters and a C-terminal nuclease module that is sui generis. PrrC homologs are prevalent in many other bacteria. Here we report that Haemophilus influenzae PrrC is toxic in E. coli and yeast. To illuminate structure-activity relations, we conducted a new round of mutational analysis of EcoPrrC guided by primary structure conservation among toxic PrrC homologs. We indentify 17 candidate active site residues in the NTPase module that are essential for toxicity in yeast when EcoPrrC is expressed at high gene dosage. Their functions could be educed by integrating mutational data with the atomic structure of the transition-state complex of a homologous ABC protein.
authors.affiliation: Molecular Biology Program, Sloan-Kettering Institute, New York, NY 10065, USA.
authors.forename: Birthe
authors.initials: B
authors.lastname: Meineke
authors.forename: Stewart
authors.initials: S
authors.lastname: Shuman
mesh_terms: D000595:Amino Acid Sequence; D004926:Escherichia coli / Q000378:metabolism / Q000821:virology*; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009154:Mutation; D043583:Nucleoside-Triphosphatase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D010957:Plasmids; D011401:Promoter Regions, Genetic; D011487:Protein Conformation; D017434:Protein Structure, Tertiary / Q000235:genetics / Q000502:physiology*; D012260:Ribonucleases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000187:drug effects; D013329:Structure-Activity Relationship
chemical_list: D029968:Escherichia coli Proteins; C084965:PrrC protein, E coli; D012260:Ribonucleases; D043583:Nucleoside-Triphosphatase