title: Cooperative and critical roles for both G domains in the GTPase activity and cellular function of ribosome-associated Escherichia coli EngA.
abstract: To probe the cellular phenotype and biochemical function associated with the G domains of Escherichia coli EngA (YfgK, Der), mutations were created in the phosphate binding loop of each. Neither an S16A nor an S217A variant of G domain 1 or 2, respectively, was able to support growth of an engA conditional null. Polysome profiles of EngA-depleted cells were significantly altered, and His(6)-EngA was found to cofractionate with the 50S ribosomal subunit. The variants were unable to complement the abnormal polysome profile and were furthermore significantly impacted with respect to in vitro GTPase activity. Together, these observations suggest that the G domains have a cooperative function in ribosome stability and/or biogenesis.
authors.affiliation: Antimicrobial Research Centre, Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario L8N 3Z5, Canada.
authors.forename: Amrita
authors.initials: A
authors.lastname: Bharat
authors.forename: Mengxi
authors.initials: M
authors.lastname: Jiang
authors.forename: Susan M
authors.initials: SM
authors.lastname: Sullivan
authors.forename: Janine R
authors.initials: JR
authors.lastname: Maddock
authors.forename: Eric D
authors.initials: ED
authors.lastname: Brown
mesh_terms: D004926:Escherichia coli / Q000254:growth & development* / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D019204:GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D006639:Histidine; D017354:Point Mutation; D011132:Polyribosomes / Q000378:metabolism*; D014176:Protein Biosynthesis; D017434:Protein Structure, Tertiary / Q000235:genetics / Q000502:physiology*; D012270:Ribosomes / Q000201:enzymology* / Q000378:metabolism
chemical_list: D029968:Escherichia coli Proteins; D006639:Histidine; D019204:GTP-Binding Proteins