Target type: biologicalprocess
The aggregation, arrangement and bonding together of constituent RNAs and proteins to form the small ribosomal subunit. [GOC:jl, PMID:30467428]
The formation of the small ribosomal subunit (40S in eukaryotes, 30S in prokaryotes) is a complex and highly regulated process, essential for protein synthesis. This assembly involves the coordinated interaction of ribosomal RNAs (rRNAs) and ribosomal proteins (r-proteins) in a stepwise manner. The process can be broadly divided into the following stages:
1. **Transcription and Processing of rRNA:** The rRNA precursor molecule is transcribed from the DNA and then processed by a series of enzymatic steps, including cleavage and modification of the rRNA molecule. This generates the mature rRNA molecules that will form the core of the ribosomal subunit.
2. **Initial Assembly of rRNA:** The processed rRNA molecules fold into specific secondary and tertiary structures, forming the core of the ribosomal subunit. These structures provide a framework for the binding of ribosomal proteins.
3. **Binding of Ribosomal Proteins:** Ribosomal proteins bind to the rRNA molecule in a specific order. This binding is guided by both rRNA structure and protein-protein interactions. The binding of each r-protein helps to stabilize the rRNA structure and to recruit other r-proteins to the complex.
4. **Maturation and Quality Control:** The assembly process is subject to quality control mechanisms. Errors in assembly can lead to the formation of non-functional ribosomes, which can have deleterious effects on protein synthesis. This quality control involves the removal of misfolded rRNA or improperly assembled subunits.
5. **Export to the Cytoplasm:** Once the small ribosomal subunit is fully assembled, it is exported from the nucleus to the cytoplasm. In eukaryotes, this process is facilitated by export receptor proteins.
The specific details of this process can vary between organisms, but the general principles of rRNA processing, protein binding, and quality control are conserved. This complex assembly pathway ensures the accurate formation of functional ribosomes, which are essential for the translation of mRNA into proteins.'
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| Protein | Definition | Taxonomy |
|---|---|---|
| 30S ribosomal protein S19 | A small ribosomal subunit protein uS19 that is encoded in the genome of Escherichia coli K-12. [PRO:DNx, UniProtKB:P0A7U3] | Escherichia coli K-12 |
| 30S ribosomal protein S21 | A small ribosomal subunit protein bS21 that is encoded in the genome of Escherichia coli K-12. [PRO:DNx, UniProtKB:P68679] | Escherichia coli K-12 |
| 30S ribosomal protein S1 | A small ribosomal subunit protein bS1 that is encoded in the genome of Escherichia coli K-12. [PRO:DNx, UniProtKB:P0AG67] | Escherichia coli K-12 |
| 30S ribosomal protein S17 | A small ribosomal subunit protein uS17 that is encoded in the genome of Escherichia coli K-12. [PRO:DNx, UniProtKB:P0AG63] | Escherichia coli K-12 |
| 30S ribosomal protein S14 | A small ribosomal subunit protein uS14 that is encoded in the genome of Escherichia coli K-12. [PRO:DNx, UniProtKB:P0AG59] | Escherichia coli K-12 |
| 30S ribosomal protein S15 | A small ribosomal subunit protein uS15 that is encoded in the genome of Escherichia coli K-12. [PRO:DNx, UniProtKB:P0ADZ4] | Escherichia coli K-12 |
| 30S ribosomal protein S8 | A small ribosomal subunit protein uS8 that is encoded in the genome of Escherichia coli K-12. [PRO:DNx, UniProtKB:P0A7W7] | Escherichia coli K-12 |
| 30S ribosomal protein S5 | A small ribosomal subunit protein uS5 that is encoded in the genome of Escherichia coli K-12. [PRO:DNx, UniProtKB:P0A7W1] | Escherichia coli K-12 |
| 30S ribosomal protein S4 | A small ribosomal subunit protein uS4 that is encoded in the genome of Escherichia coli K-12. [PRO:DNx, UniProtKB:P0A7V8] | Escherichia coli K-12 |
| 30S ribosomal protein S3 | A small ribosomal subunit protein uS3 that is encoded in the genome of Escherichia coli K-12. [PRO:DNx, UniProtKB:P0A7V3] | Escherichia coli K-12 |
| 30S ribosomal protein S2 | A small ribosomal subunit protein uS2 that is encoded in the genome of Escherichia coli K-12. [PRO:DNx, UniProtKB:P0A7V0] | Escherichia coli K-12 |
| 30S ribosomal protein S20 | A small ribosomal subunit protein bS20 that is encoded in the genome of Escherichia coli K-12. [PRO:DNx, UniProtKB:P0A7U7] | Escherichia coli K-12 |
| 30S ribosomal protein S16 | A small ribosomal subunit protein bS16 that is encoded in the genome of Escherichia coli K-12. [PRO:DNx, UniProtKB:P0A7T3] | Escherichia coli K-12 |
| 30S ribosomal protein S7 | A small ribosomal subunit protein uS7 that is encoded in the genome of Escherichia coli K-12. [PRO:DNx, UniProtKB:P02359] | Escherichia coli K-12 |
| 30S ribosomal protein S7 | A small ribosomal subunit protein uS7 that is encoded in the genome of Escherichia coli K-12. [PRO:DNx, UniProtKB:P02359] | Escherichia coli K-12 |
| 40S ribosomal protein S27 | A small ribosomal subunit protein eS27 that is encoded in the genome of human. [PRO:DNx, UniProtKB:P42677] | Homo sapiens (human) |
| 40S ribosomal protein S5 | A eukaryotic-type small ribosomal subunit protein uS7 that is encoded in the genome of human. [PRO:DNx, UniProtKB:P46782] | Homo sapiens (human) |
| 40S ribosomal protein SA | A eukaryotic-type small ribosomal subunit protein uS2 that is encoded in the genome of human. [PRO:DNx, UniProtKB:P08865] | Homo sapiens (human) |
| 40S ribosomal protein S28 | A small ribosomal subunit protein eS28 that is encoded in the genome of human. [PRO:DNx, UniProtKB:P62857] | Homo sapiens (human) |
| 40S ribosomal protein S15 | A eukaryotic-type small ribosomal subunit protein uS19 that is encoded in the genome of human. [PRO:DNx, UniProtKB:P62841] | Homo sapiens (human) |
| 40S ribosomal protein S14 | A eukaryotic-type small ribosomal subunit protein uS11 that is encoded in the genome of human. [PRO:DNx, UniProtKB:P62263] | Homo sapiens (human) |
| 40S ribosomal protein S19 | A small ribosomal subunit protein eS19 that is encoded in the genome of human. [PRO:DNx, UniProtKB:P39019] | Homo sapiens (human) |
| Compound | Definition | Classes | Roles |
|---|---|---|---|
| chloramphenicol | Amphenicol: Chloramphenicol and its derivatives. | C-nitro compound; carboxamide; diol; organochlorine compound | antibacterial drug; antimicrobial agent; Escherichia coli metabolite; geroprotector; Mycoplasma genitalium metabolite; protein synthesis inhibitor |
| framycetin | framycetin : A tetracyclic antibacterial agent derived from neomycin, being a glycoside ester of neamine and neobiosamine B. Framycetin: A component of NEOMYCIN that is produced by Streptomyces fradiae. On hydrolysis it yields neamine and neobiosamine B. (From Merck Index, 11th ed) | aminoglycoside | allergen; antibacterial drug; Escherichia coli metabolite |
| erythromycin | erythromycin : Any of several wide-spectrum macrolide antibiotics obtained from actinomycete Saccharopolyspora erythraea (formerly known as Streptomyces erythraeus). erythromycin A : An erythromycin that consists of erythronolide A having 2,6-dideoxy-3-C-methyl-3-O-methyl-alpha-L-ribo-hexopyranosyl and 3,4,6-trideoxy-3-(dimethylamino)-beta-D-xylo-hexopyranosyl residues attahced at positions 4 and 6 respectively. Erythromycin: A bacteriostatic antibiotic macrolide produced by Streptomyces erythreus. Erythromycin A is considered its major active component. In sensitive organisms, it inhibits protein synthesis by binding to 50S ribosomal subunits. This binding process inhibits peptidyl transferase activity and interferes with translocation of amino acids during translation and assembly of proteins. | cyclic ketone; erythromycin | |
| neamine | neamine : 2-Deoxy-D-streptamine glycosylated at the 4-oxygen with a 6-amino-alpha-D-glucosaminyl group. neamine: fragment of NEOMYCIN B; structure in first source | 2,6-dideoxy-alpha-D-glucoside; aminoglycoside | antibacterial agent |
| florfenicol | florfenicol : A carboxamide that is the N-dichloroacetyl derivative of (1R,2S)-2-amino-3-fluoro-1-[4-(methanesulfonyl)phenyl]propan-1-ol. A synthetic veterinary antibiotic that is used for treatment of bovine respiratory disease and foot rot; also used in aquaculture. florfenicol: structure given in first source | organochlorine compound; organofluorine compound; secondary alcohol; secondary carboxamide; sulfone | antimicrobial agent |
| antibiotic g 418 | antibiotic G 418: from Micromonospora rhodorangea | ||
| paromomycin | paromomycin : An amino cyclitol glycoside that is the 1-O-(2-amino-2-deoxy-alpha-D-glucopyranoside) and the 3-O-(2,6-diamino-2,6-dideoxy-beta-L-idopyranosyl)-beta-D-ribofuranoside of 4,6-diamino-2,3-dihydroxycyclohexane (the 1R,2R,3S,4R,6S diastereoisomer). It is obtained from various Streptomyces species. A broad-spectrum antibiotic, it is used (generally as the sulfate salt) for the treatment of acute and chronic intestinal protozoal infections, but is not effective for extraintestinal protozoal infections. It is also used as a therapeutic against visceral leishmaniasis. Paromomycin: An aminoglycoside antibacterial and antiprotozoal agent produced by species of STREPTOMYCES. | amino cyclitol glycoside; aminoglycoside antibiotic | anthelminthic drug; antibacterial drug; antiparasitic agent; antiprotozoal drug |
| puromycin | puromycins | antiinfective agent; antimicrobial agent; antineoplastic agent; EC 3.4.11.14 (cytosol alanyl aminopeptidase) inhibitor; EC 3.4.14.2 (dipeptidyl-peptidase II) inhibitor; nucleoside antibiotic; protein synthesis inhibitor | |
| netilmicin | Netilmicin: Semisynthetic 1-N-ethyl derivative of SISOMYCIN, an aminoglycoside antibiotic with action similar to gentamicin, but less ear and kidney toxicity. | ||
| linezolid | acetamides; morpholines; organofluorine compound; oxazolidinone | antibacterial drug; protein synthesis inhibitor | |
| zithromax | azithromycin : A macrolide antibiotic useful for the treatment of bacterial infections. Azithromycin: A semi-synthetic macrolide antibiotic structurally related to ERYTHROMYCIN. It has been used in the treatment of Mycobacterium avium intracellulare infections, toxoplasmosis, and cryptosporidiosis. | macrolide antibiotic | antibacterial drug; environmental contaminant; xenobiotic |
| tiamulin | tiamulin : A carbotricyclic compound that is pleuromutilin in which the hydroxyacetate group is replaced by a 2-{[2-(diethylamino)ethyl]sulfanyl}acetate group. An antibacterial drug, tiamulin is used in veterinary medicine (generally as its hydrogen fumarate salt) for the treatment of swine dysentery caused by Serpulina hyodysenteriae. tiamulin: 81723 HFU and tiamutin are for fumarate salt; prevents senescence in ascomycete; pleuromutilin derivative; RN given refers to ((3aS-(3aalpha,4beta,5alpha,6alpha,8beta,9alpha,9abeta,10S*))-isomer | carbotricyclic compound; carboxylic ester; cyclic ketone; organic sulfide; secondary alcohol; semisynthetic derivative; tertiary amino compound; tetracyclic diterpenoid | antibacterial drug |
| hmr 3647 | |||
| josamycin | acetate ester; aldehyde; disaccharide derivative; glycoside; macrolide antibiotic; tertiary alcohol; tertiary amino compound | antibacterial drug; metabolite | |
| albocycline | albocycline: macrolide antibiotic isolated from Streptomyces bruneogriseus nov. sp. MCRL-0129; specifically anti-staphylococcal, including antibiotic-resistant strains; structure | macrolide | |
| evernimicin | |||
| gentamicin sulfate | |||
| gentamicin sulfate | |||
| pristinamycin iib | virginiamycin M2: structure in first source | ||
| cem 101 | solithromycin: an antibacterial fluoroketolide; structure in first source | ||
| tetracycline | tetracycline : A broad-spectrum polyketide antibiotic produced by the Streptomyces genus of actinobacteria. Tetracycline: A naphthacene antibiotic that inhibits AMINO ACYL TRNA binding during protein synthesis. | ||
| eravacycline | eravacycline: has antibacterial activity | tetracyclines | |
| PF-06446846 | PF-06446846 : A triazolopyridine that is 3H-[1,2,3]triazolo[4,5-b]pyridine substituted by a 4-{(3-chloropyridin-2-yl)[(3R)-piperidin-3-yl]carbamoyl}phenyl group at position 3. It is a potent inhibitor of PCSK9. PF-06446846: inhibits translation of PCSK9 ;structure in first source | benzamides; monochloropyridine; piperidines; tertiary carboxamide; triazolopyridine | antilipemic drug; EC 3.4.21.61 (kexin) inhibitor |