Page last updated: 2024-10-24
small ribosomal subunit
Definition
Target type: cellularcomponent
The smaller of the two subunits of a ribosome. [GOC:mah]
The small ribosomal subunit (40S in eukaryotes, 30S in prokaryotes) is a complex molecular machine responsible for decoding messenger RNA (mRNA) and facilitating the initiation of protein synthesis. It is composed of a single ribosomal RNA (rRNA) molecule and approximately 33 proteins (in eukaryotes). The 40S subunit in eukaryotes consists of 18S rRNA and 33 ribosomal proteins. The 18S rRNA forms the core structure of the subunit, providing a framework for the assembly of the ribosomal proteins. The proteins are involved in a variety of functions, including:
* **mRNA binding**: The small subunit binds to the 5' cap of mRNA and scans along the molecule until it encounters the start codon (AUG).
* **Initiation factor binding**: The small subunit interacts with initiation factors (eIFs) that are essential for the assembly of the ribosome on mRNA and the recruitment of the initiator tRNA.
* **Decoding**: The small subunit contains the decoding center, which ensures that the correct tRNA molecule is selected to match the mRNA codon.
* **Ribosome assembly**: The ribosomal proteins interact with each other and the rRNA to form the complex structure of the small subunit.
The small ribosomal subunit is a dynamic structure that undergoes conformational changes during the initiation, elongation, and termination phases of protein synthesis. These changes are essential for the proper function of the ribosome.
In summary, the small ribosomal subunit is a highly complex and essential component of the protein synthesis machinery. It plays a crucial role in mRNA decoding, initiation factor binding, and ribosome assembly.'
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Proteins (22)
| Protein | Definition | Taxonomy |
|---|---|---|
| 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 S10 | A small ribosomal subunit protein uS10 that is encoded in the genome of Escherichia coli K-12. [PRO:DNx, UniProtKB:P0A7R5] | 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 S13 | A small ribosomal subunit protein uS13 that is encoded in the genome of Escherichia coli K-12. [PRO:DNx, UniProtKB:P0A7S9] | 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 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 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 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 S12 | A small ribosomal subunit protein uS12 that is encoded in the genome of Escherichia coli K-12. [PRO:DNx, UniProtKB:P0A7S3] | 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 S21 | A small ribosomal subunit protein eS21 that is encoded in the genome of human. [PRO:DNx, UniProtKB:P63220] | Homo sapiens (human) |
| 40S ribosomal protein S30 | A ubiquitin-like FUBI-ribosomal protein eS30 fusion protein that is encoded in the genome of human. [PRO:DAN, UniProtKB:P62861] | 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 S26 | A small ribosomal subunit protein eS26 that is encoded in the genome of human. [PRO:DNx, UniProtKB:P62854] | Homo sapiens (human) |
| 40S ribosomal protein S25 | A small ribosomal subunit protein eS25 that is encoded in the genome of human. [PRO:DNx, UniProtKB:P62851] | Homo sapiens (human) |
| 40S ribosomal protein S24 | A small ribosomal subunit protein eS24 that is encoded in the genome of human. [PRO:DNx, UniProtKB:P62847] | Homo sapiens (human) |
| 40S ribosomal protein S6 | A small ribosomal subunit protein eS6 that is encoded in the genome of human. [PRO:DNx, UniProtKB:P62753] | Homo sapiens (human) |
| 40S ribosomal protein S4, X isoform | A small ribosomal subunit protein eS4, X isoform that is encoded in the genome of human. [PRO:DNx, UniProtKB:P62701] | Homo sapiens (human) |
| 40S ribosomal protein S29 | A eukaryotic-type small ribosomal subunit protein uS14 that is encoded in the genome of human. [PRO:DNx, UniProtKB:P62273] | Homo sapiens (human) |
| 40S ribosomal protein S18 | A eukaryotic-type small ribosomal subunit protein uS13 that is encoded in the genome of human. [PRO:DNx, UniProtKB:P62269] | Homo sapiens (human) |
| 40S ribosomal protein S16 | A eukaryotic-type small ribosomal subunit protein uS9 that is encoded in the genome of human. [PRO:DNx, UniProtKB:P62249] | Homo sapiens (human) |
Compounds (23)
| 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 |