title: Functional interaction between ribosomal protein L6 and RbgA during ribosome assembly.
abstract: RbgA is an essential GTPase that participates in the assembly of the large ribosomal subunit in Bacillus subtilis and its homologs are implicated in mitochondrial and eukaryotic large subunit assembly. How RbgA functions in this process is still poorly understood. To gain insight into the function of RbgA we isolated suppressor mutations that partially restored the growth of an RbgA mutation (RbgA-F6A) that caused a severe growth defect. Analysis of these suppressors identified mutations in rplF, encoding ribosomal protein L6. The suppressor strains all accumulated a novel ribosome intermediate that migrates at 44S in sucrose gradients. All of the mutations cluster in a region of L6 that is in close contact with helix 97 of the 23S rRNA. In vitro maturation assays indicate that the L6 substitutions allow the defective RbgA-F6A protein to function more effectively in ribosome maturation. Our results suggest that RbgA functions to properly position L6 on the ribosome, prior to the incorporation of L16 and other late assembly proteins.
authors.affiliation: Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, United States of America.
authors.forename: Megha
authors.initials: M
authors.lastname: Gulati
authors.affiliation: Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, United States of America.
authors.forename: Nikhil
authors.initials: N
authors.lastname: Jain
authors.affiliation: Department of Integrative Structural and Computational Biology, Department of Chemistry and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, California, United States of America.
authors.forename: Joseph H
authors.initials: JH
authors.lastname: Davis
authors.affiliation: Department of Integrative Structural and Computational Biology, Department of Chemistry and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, California, United States of America.
authors.forename: James R
authors.initials: JR
authors.lastname: Williamson
authors.affiliation: Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, United States of America.
authors.forename: Robert A
authors.initials: RA
authors.lastname: Britton
mesh_terms: D001412:Bacillus subtilis / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D012338:RNA, Ribosomal, 23S / Q000737:chemistry / Q000378:metabolism; D012269:Ribosomal Proteins / Q000235:genetics / Q000378:metabolism*; D054681:Ribosome Subunits, Large, Bacterial / Q000378:metabolism; D012270:Ribosomes / Q000235:genetics / Q000378:metabolism*; D013489:Suppression, Genetic
chemical_list: D001426:Bacterial Proteins; D012338:RNA, Ribosomal, 23S; D012269:Ribosomal Proteins; C027937:ribosomal protein L16; C031249:ribosomal protein L6