Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.26.3 (RNase III)
 1,015 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The synthesis rates of ribonuclease III (RNase III) and Era proteins are relatively low, and expression of the era gene is translationally coupled with expression of the rnc gene. Expression of both genes is negatively controlled by RNase III itself. We have constructed plasmids that overproduce RNase III and/or Era proteins under the control of the lambda PL promoter. A plasmid with the rnc gene under PL control expresses RNase III at levels greater than 40% of total cellular protein. Another plasmid with the era gene under PL control and a modified translation-initiation signal produces up to 80% of total cell protein as Era. Each protein has been purified using simple and rapid procedures. Purified RNase III protein specifically processes mRNA transcripts containing known RNase III sites. The purified Era protein binds GDP and GTP and has GTPase activity. Kinetic analysis shows that one molecule of GTP or GDP is bound/Era peptide with a Kd of 5.5 microM for GTP binding and 1.0 microM for GDP binding. The Km of the Era GTPase is 9.0 microM, and the maximum catalyzed rate of GTP hydrolyzed/min/mol of Era protein at 37 degrees C is 9.8 mmol.
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PMID:Expression and characterization of RNase III and Era proteins. Products of the rnc operon of Escherichia coli. 210 34

Era is a low-molecular-weight GTPase essential for Escherichia coli viability. The gene encoding Era is found in the rnc operon, and the synthesis of both RNase III and Era increases with growth rate. Mutants that are partially defective in Era GTPase activity or that are reduced in the synthesis of wild-type Era become arrested in the cell cycle at the predivisional two-cell stage. The partially defective Era GTPase mutation (era1) suppresses several temperature-sensitive lethal alleles that affect chromosome replication and chromosome partitioning but not cell division. Our results suggest that Era plays an important role in cell cycle progression at a specific point in the cycle, after chromosome partitioning but before cytokinesis. Possible functions for Era in cell cycle progression and the initiation of cell division are discussed.
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PMID:Cell cycle arrest in Era GTPase mutants: a potential growth rate-regulated checkpoint in Escherichia coli. 951