Literature summary for 3.1.26.3 extracted from

Lim, B.; Sim, M.; Lee, H.; Hyun, S.; Lee, Y.; Hahn, Y.; Shin, E.; Lee, K.
Regulation of Escherichia coli RNase III activity (2015), J. Microbiol., 53, 487-494 .

Search for more literature for 3.1.26.3

Metals/Ions

Metals/Ions	Comment	Organism	Structure
Co2+	activates	Escherichia coli
Mg2+	RNase III requires two transition metal ions to stabilize the catalytic valley where it cleaves dsRNA. Mg2+ is the most favored metal ion in the case of Escherichia coli RNase III. Two Mg2+ ions interact with negatively charged amino acids and form a hydrogen bond with nucleotide residues of cleavage sites within each catalytic site	Escherichia coli
Mn2+	activates	Escherichia coli
additional information	RNase III requires two transition metal ions to stabilize the catalytic valley where it cleaves dsRNAI	Aquifex aeolicus
additional information	while Mn2+, Ni2+, and Co2+ can also support the catalytic activity of RNase III in vitro, extracellular levels of Ni2+ and Co2+ do not significantly alter RNase III activity	Escherichia coli
Ni2+	activates	Escherichia coli

Organism

Organism	UniProt	Comment	Textmining
Aquifex aeolicus	O67082	-	-
Escherichia coli	P0A7Y0	-	-

Posttranslational Modification

Posttranslational Modification	Comment	Organism
phosphoprotein	RNase III undergoes serine phosphorylation in the T7 virus-infected cell, which enhances its catalytic activity by 3-5 fold	Escherichia coli

Reaction

Reaction	Comment	Organism	Reaction ID
Endonucleolytic cleavage to a 5'-phosphomonoester	mechanism of RNase III catalytic action, overview. Endoribonucleolytic activity of RNase III produces 2-nucleotide 3'-OH overhang at the end of dsRNA substrates	Escherichia coli	a

Substrates and Products (Substrate)

Substrates	Comment Substrates	Organism	Products	Comment (Products)	Rev.	Reac.
additional information	bdm, corA, mltD, proU, betT, and proP mRNAs are used as RNase III substrates, cleavage site determination reveals that no distinct consensus sequences, which would account for the specificity of RNase III recognition and cleavage process, are observed when in vivo RNase III substrates are analyzed	Escherichia coli	?	-	?

Subunits

Subunits	Comment	Organism
dimer	the active form of Escherichia coli RNase III consists of an endonuclease domain (EndoND) and a double stranded RNA binding domain (dsRBD) combined in a dimer of two 25 kDa polypeptides. The RNase III dsRBD exhibits an alphabetabetabetaalpha fold, which is a common form of eukaryotic proteins that recognize dsRNA. EndoND comprises seven alpha-helices and a 310 helix. It homodimerizes through hydrophobic interactions, creating a ball-and-socket junction and a large catalytic valley	Escherichia coli

Synonyms

Synonyms	Comment	Organism
RNase III	-	Escherichia coli
RNase III	-	Aquifex aeolicus
rnc	-	Aquifex aeolicus

Expression

Organism	Comment	Expression
Escherichia coli	the RNase III operon includes the rnc and era genes encoding RNase III and Era proteins, respectively. RNase III cleaves its own leader RNA, causing instability of its mRNA. Thus, RNase III can repress its own synthesis and also that of Era, because era is transcriptionally and translationally coupled to rnc expression. Era function is critical for maintaining cell growth and cell division rate in Escherichia coli, so that the regulation of Era levels by RNase III has been proposed as an important feature of the Escherichia coli cell cycle	down

General Information

General Information	Comment	Organism
evolution	RNase III is a member of the phylogenetically highly conserved endoribonuclease III family	Escherichia coli
evolution	RNase III is a member of the phylogenetically highly conserved endoribonuclease III family	Aquifex aeolicus
metabolism	RNase III activity during various environmental stresses, overview	Aquifex aeolicus
metabolism	RNase III plays a key role in posttranscriptional regulatory pathways in Escherichia coli. RNase III-mediated regulation of environmental stress-related genes provide evidence of the critical role of RNase III in rapid cellular responses to various stress conditions. Although regulation of such genes by RNase III is essential for bacteria to adapt to a wide range of environmental conditions that they encounter in nature, the exact mode of substrate recognition and mechanisms underlying the regulation of RNase III activity is not fully understood, RNase III activity during various environmental stresses, overview. Mechanisms of RNase III-mediated regulation of a subgroup of mRNA species including bdm, betT, proP, and proU whose protein products are associated with the cellular response to osmotic stress	Escherichia coli
additional information	crystallographic and modeling studies of RNase III from Aquifex aeolicus suggest that highly conserved six negatively charged residues, including E40/D44/D107/E110 and E37/E64, create two potential RNA cleavage sites within the catalytic valley	Aquifex aeolicus
physiological function	RNase III activity during various environmental stresses, overview	Aquifex aeolicus
physiological function	RNase III plays a role in rRNA and tRNA maturation in Escherichia coli. RNase III enzymatic activity can be regulated on multiple levels that include autoregulation by cleavage of its own mRNA message. The primary 30S rRNA transcript, which includes all of the rRNA genes, is cleaved by RNase III within the flanking double-stranded regions. This generates the 17S precursor of the 16S rRNA and the p23S precursor of the 23S rRNA. RNase III-mediated regulation of environmental stress-related genes provide evidence of the critical role of RNase III in rapid cellular responses to various stress conditions. Although regulation of such genes by RNase III is essential for bacteria to adapt to a wide range of environmental conditions that they encounter in nature, the exact mode of substrate recognition and mechanisms underlying the regulation of RNase III activity is not fully understood, RNase III activity during various environmental stresses, overview. Osmoregulation of RNase III activity, the osmoregulatory K+ uptake is mediated by the Trk and Kdp transporters. Analysis of substrate RNA molecules bound to RNase III by in vivo crosslinking and immunoprecipitation of RNase III indicated that downregulation of RNase III cleavage activity under hyperosmotic stress is caused by the decreased RNA binding capacity of RNase III. Autoregulation, Modulation of RNase III activity induced by antibiotic stress. RNase III can also be regulated by trans-acting factors, e.g. YmdB. T7 protein kinase positively regulates RNase III in Escherichia coli	Escherichia coli

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Release 2023.1 (January 2023)