Target type: biologicalprocess
Any process involved in forming the mature 3' end of an rRNA molecule. [GOC:mah]
rRNA 3'-end processing is a crucial step in ribosome biogenesis, ensuring the proper maturation and functionality of ribosomal RNA (rRNA). This process involves the precise removal of extraneous sequences from the 3' end of rRNA precursors, generating mature rRNA molecules that can participate in protein synthesis.
The process begins with the transcription of rRNA genes, generating long precursor rRNA molecules containing both functional and non-functional sequences. The 3' end processing of rRNA is a multi-step process that involves several enzymatic activities, including:
1. **Cleavage**: The first step involves the precise cleavage of the precursor rRNA at the 3' end by specific endonucleases. This cleavage event is often guided by specific sequence motifs within the rRNA precursor.
2. **Exonucleolytic trimming**: After the initial cleavage, exonucleases, such as the 3'-5' exoribonucleases, remove nucleotides from the 3' end of the cleaved rRNA, further refining the 3' end.
3. **Base modification**: In some cases, the 3' end of the rRNA undergoes base modifications, such as methylation or pseudouridylation. These modifications can play a role in the stability and functionality of the mature rRNA.
4. **Addition of a 3'-terminal nucleotide**: The final step in the 3' end processing of rRNA involves the addition of a specific nucleotide, often an adenine residue, to the 3' end of the mature rRNA. This process, known as polyadenylation, can play a role in the stability and translation of the rRNA.
The precise mechanisms and components involved in rRNA 3' end processing can vary depending on the organism and the specific rRNA molecule being processed. However, the overall goal is to generate mature rRNA molecules with the correct 3' end structure, ensuring their proper function in protein synthesis. Deficiencies in rRNA 3' end processing can lead to ribosome dysfunction and impaired protein synthesis, potentially resulting in developmental defects and disease.'
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| Protein | Definition | Taxonomy |
|---|---|---|
| Ribonuclease T | A ribonuclease T that is encoded in the genome of Escherichia coli K-12. [PRO:DNx, UniProtKB:P30014] | Escherichia coli K-12 |
| Compound | Definition | Classes | Roles |
|---|---|---|---|
| citric acid, anhydrous | citric acid : A tricarboxylic acid that is propane-1,2,3-tricarboxylic acid bearing a hydroxy substituent at position 2. It is an important metabolite in the pathway of all aerobic organisms. Citric Acid: A key intermediate in metabolism. It is an acid compound found in citrus fruits. The salts of citric acid (citrates) can be used as anticoagulants due to their calcium chelating ability. | tricarboxylic acid | antimicrobial agent; chelator; food acidity regulator; fundamental metabolite |
| aurintricarboxylic acid | aurintricarboxylic acid : A member of the class of quinomethanes that is 3-methylidene-6-oxocyclohexa-1,4-diene-1-carboxylic acid in which the methylidene hydrogens are replaced by 4-carboxy-3-hydroxyphenyl groups. The trisodium salt is the biological stain 'chrome violet CG' while the triammonium salt is 'aluminon'. Aurintricarboxylic Acid: A dye which inhibits protein biosynthesis at the initial stages. The ammonium salt (aluminon) is a reagent for the colorimetric estimation of aluminum in water, foods, and tissues. | monohydroxybenzoic acid; quinomethanes; tricarboxylic acid | fluorochrome; histological dye; insulin-like growth factor receptor 1 antagonist |
| dithionitrobenzoic acid | dithionitrobenzoic acid : An organic disulfide that results from the formal oxidative dimerisation of 2-nitro-5-thiobenzoic acid. An indicator used to quantify the number or concentration of thiol groups. Dithionitrobenzoic Acid: A standard reagent for the determination of reactive sulfhydryl groups by absorbance measurements. It is used primarily for the determination of sulfhydryl and disulfide groups in proteins. The color produced is due to the formation of a thio anion, 3-carboxyl-4-nitrothiophenolate. | nitrobenzoic acid; organic disulfide | indicator |
| 7-nitro-1h-indole-2-carboxylic acid | 7-nitro-1H-indole-2-carboxylic acid: acts on AP endonuclease, 3'-phosphodiesterase, and 3'-phosphatase activities of APE1; structure in first source |