In vivo studies on the incorporation of microinjected acidic proteins of the large ribosomal subunit from Escherichia coli and Artemia salina into oocyte ribosomes from Xenopus laevis

Biochemistry ◽  
1979 ◽  
Vol 18 (19) ◽  
pp. 4144-4147 ◽  
Author(s):  
Holger Kalthoff ◽  
Dietmar Richter
Keyword(s):  
Escherichia Coli ◽  
Xenopus Laevis ◽  
Ribosomal Subunit ◽  
Artemia Salina ◽  
In Vivo Studies ◽  
Large Ribosomal Subunit ◽  
Acidic Proteins

scholarly journals The Escherichia coli GTPase CgtAE Is Involved in Late Steps of Large Ribosome Assembly

2006 ◽  
Vol 188 (19) ◽  
pp. 6757-6770 ◽  
Author(s):  
Mengxi Jiang ◽  
Kaustuv Datta ◽  
Angela Walker ◽  
John Strahler ◽  
Pia Bagamasbad ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Ribosomal Proteins ◽  
Large Subunit ◽  
Ribosomal Subunit ◽  
Ribosome Assembly ◽  
Macromolecular Complex ◽  
Large Ribosomal Subunit ◽  
Proteomic Approach ◽  
Temporal Relationships

ABSTRACT The bacterial ribosome is an extremely complicated macromolecular complex the in vivo biogenesis of which is poorly understood. Although several bona fide assembly factors have been identified, their precise functions and temporal relationships are not clearly defined. Here we describe the involvement of an Escherichia coli GTPase, CgtAE, in late steps of large ribosomal subunit biogenesis. CgtAE belongs to the Obg/CgtA GTPase subfamily, whose highly conserved members are predominantly involved in ribosome function. Mutations in CgtAE cause both polysome and rRNA processing defects; small- and large-subunit precursor rRNAs accumulate in a cgtAE mutant. In this study we apply a new semiquantitative proteomic approach to show that CgtAE is required for optimal incorporation of certain late-assembly ribosomal proteins into the large ribosomal subunit. Moreover, we demonstrate the interaction with the 50S ribosomal subunits of specific nonribosomal proteins (including heretofore uncharacterized proteins) and define possible temporal relationships between these proteins and CgtAE. We also show that purified CgtAE associates with purified ribosomal particles in the GTP-bound form. Finally, CgtAE cofractionates with the mature 50S but not with intermediate particles accumulated in other large ribosome assembly mutants.

scholarly journals Overproduction of SecA Suppresses the Export Defect Caused by a Mutation in the Gene Encoding the Escherichia coli Export Chaperone SecB

1999 ◽  
Vol 181 (10) ◽  
pp. 3010-3017 ◽  
Author(s):  
Heather A. Cook ◽  
Carol A. Kumamoto
Keyword(s):  
Escherichia Coli ◽  
Outer Membrane Proteins ◽  
Protein A ◽  
In Vivo Studies ◽  
Wild Type ◽  
Gene Encoding ◽  
Precursor Proteins ◽  
Additional Support ◽  
Insight Into

ABSTRACT SecB is a cytosolic protein required for rapid and efficient export of particular periplasmic and outer membrane proteins inEscherichia coli. SecB promotes export by stabilizing newly synthesized precursor proteins in a nonnative conformation and by targeting the precursors to the inner membrane. Biochemical studies suggest that SecB facilitates precursor targeting by binding to the SecA protein, a component of the membrane-embedded translocation apparatus. To gain more insight into the functional interaction of SecB and SecA, in vivo, mutations in the secA locus that compensate for the export defect caused by the secBmissense mutation secBL75Q were isolated. Two suppressors were isolated, both of which led to the overproduction of wild-type SecA protein. In vivo studies demonstrated that the SecBL75Q mutant protein releases precursor proteins at a lower rate than does wild-type SecB. Increasing the level of SecA protein in the cell was found to reverse this slow-release defect, indicating that overproduction of SecA stimulates the turnover of SecBL75Q-precursor complexes. These findings lend additional support to the proposed pathway for precursor targeting in which SecB promotes targeting to the translocation apparatus by binding to the SecA protein.

In vivo studies of the Escherichia coli RecB polypeptidelacking its nuclease center

2000 ◽  
Vol 151 (9) ◽  
pp. 769-776 ◽  
Author(s):  
Erika Salaj-Šmic ◽  
Damir Đermić ◽  
Krunoslav Brčić-Kostić ◽  
Gordana Čogelja Čajo ◽  
Željko Trgovčević
Keyword(s):  
Escherichia Coli ◽  
In Vivo Studies

scholarly journals In vivo studies of repair of 2-aminopurine in Escherichia coli.

1988 ◽  
Vol 170 (8) ◽  
pp. 3485-3492 ◽  
Author(s):  
R H Grafstrom ◽  
A Amsterdam ◽  
K Zachariasewycz
Keyword(s):  
Escherichia Coli ◽  
In Vivo Studies

scholarly journals In Vivo Studies of Active Processes in the Escherichia Coli Nucleoid

2014 ◽  
Vol 106 (2) ◽  
pp. 734a
Author(s):  
Rudra P. Kafle ◽  
Jens-Christian Meiners ◽  
Thaige Gompa
Keyword(s):  
Escherichia Coli ◽  
In Vivo Studies ◽  
Active Processes

scholarly journals Rcs and PhoPQ Regulatory Overlap in the Control of Salmonella enterica Virulence

2007 ◽  
Vol 189 (18) ◽  
pp. 6635-6644 ◽  
Author(s):  
Clara B. García-Calderón ◽  
Josep Casadesús ◽  
Francisco Ramos-Morales
Keyword(s):  
Escherichia Coli ◽  
Signal Transduction ◽  
Salmonella Enterica ◽  
In Vivo Studies ◽  
Genetic Screens ◽  
Signal Transduction System ◽  
Constitutive Activation ◽  
Regulatory Systems ◽  
Serovar Typhimurium

ABSTRACT Genetic screens based on the use of MudJ-generated lac fusions permitted the identification of novel genes regulated by the Rcs signal transduction system in Salmonella enterica serovar Typhimurium. Besides genes that are also found in the Escherichia coli genome, our screens identified Salmonella-specific genes regulated by RcsB, including bapA, siiE, srfA, and srfB. Here we show that the srfABC operon is negatively regulated by RcsB and by PhoP. In vivo studies using mutants with constitutive activation of the Rcs and/or PhoPQ system suggested that there is an overlap between these regulatory systems in the control of Salmonella virulence.

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