Pathway · 41 proteins
Ribosomal subunits
Small and large ribosomal subunits form the translation machinery.
How it works
- Bacterial small and large subunits contain rRNA and ribosomal proteins, assembled with maturation factors.
- The small subunit helps position mRNA and evaluate codon–anticodon pairing. The large subunit contains the peptidyl-transferase centre and the exit path for the growing chain.
- The subunits join in a functional translation complex and separate during recycling. A complete ribosome is not a single protein.
Grouped by the atlas’s curated pathway map. The table order is not a proven reaction order.
Its proteins
| Protein | EC | Reaction (UniProt) | Metal or cluster | Amino acids | Certainty |
|---|---|---|---|---|---|
| Small ribosomal subunit protein uS10 | — | — | — | 104 | Step named |
| Large ribosomal subunit protein uL3 | — | — | — | 241 | Step named |
| Large ribosomal subunit protein uL4 | — | — | — | 199 | Step named |
| Large ribosomal subunit protein uL23 | — | — | — | 103 | Step named |
| Large ribosomal subunit protein uL2 | — | — | — | 304 | Step named |
| Small ribosomal subunit protein uS3 | — | — | — | 212 | Step named |
| Large ribosomal subunit protein uL16 | — | — | — | 142 | Step named |
| Small ribosomal subunit protein uS17 | — | — | — | 107 | Step named |
| Small ribosomal subunit protein bS6 | — | — | — | 110 | Step named |
| Large ribosomal subunit protein bL17 | — | — | — | 118 | Step named |
| Small ribosomal subunit protein uS4 | — | — | — | 211 | Step named |
| Small ribosomal subunit protein uS11 | — | — | — | 125 | Step named |
| Small ribosomal subunit protein uS13 | — | — | — | 126 | Step named |
| Large ribosomal subunit protein bL36 | — | — | Zn(2+) | 37 | Step named |
| Large ribosomal subunit protein bL28 | — | — | — | 69 | Step named |
| Large ribosomal subunit protein bL32 | — | — | — | 63 | Step named |
| Small ribosomal subunit protein bS16 | — | — | — | 112 | Step named |
| Small ribosomal subunit protein bS1 | — | — | — | 535 | Step named |
| Large ribosomal subunit protein uL15 | — | — | — | 149 | Step named |
| Small ribosomal subunit protein uS5 | — | — | — | 208 | Step named |
| Large ribosomal subunit protein uL18 | — | — | — | 124 | Step named |
| Large ribosomal subunit protein uL6 | — | — | — | 183 | Step named |
| Large ribosomal subunit protein uL5 | — | — | — | 188 | Step named |
| Large ribosomal subunit protein uL24 | — | — | — | 132 | Step named |
| Large ribosomal subunit protein uL14 | — | — | — | 121 | Step named |
| Small ribosomal subunit protein bS20 | — | — | — | 94 | Step named |
| Small ribosomal subunit protein uS7A | — | — | — | 160 | Step named |
| Small ribosomal subunit protein uS12 | — | — | — | 128 | Step named |
| Large ribosomal subunit protein uL13 | — | — | — | 144 | Step named |
| Small ribosomal subunit protein uS9 | — | — | — | 147 | Step named |
| Large ribosomal subunit protein uL11 | — | — | — | 145 | Step named |
| Large ribosomal subunit protein uL1 | — | — | — | 242 | Step named |
| Large ribosomal subunit protein uL10 | — | — | — | 199 | Step named |
| Large ribosomal subunit protein bL12 | — | — | — | 128 | Step named |
| Large ribosomal subunit protein bL19 | — | — | — | 154 | Step named |
| Small ribosomal subunit protein uS2 | — | — | — | 274 | Step named |
| Large ribosomal subunit protein bL9 | — | — | — | 149 | Step named |
| Ribosomal protein L11 methyltransferase | 2.1.1.- | L-lysyl-[protein] + 3 S-adenosyl-L-methionine = N(6),N(6),N(6)-trimethyl-L-lysyl-[protein] + 3 S-adenosyl-L-homocysteine + 3 H(+) | — | 245 | Step named |
| General stress protein CTC | — | — | — | 151 | Step named |
| Ribosomal protein uS12 methylthiotransferase RimO | 2.8.4.4 | L-aspartate(89)-[ribosomal protein uS12]-hydrogen + (sulfur carrier)-SH + AH2 + 2 S-adenosyl-L-methionine = 3-methylsulfanyl-L-aspartate(89)-[ribosomal protein uS12]-hydrogen + (sulfur carrier)-H + 5'-deoxyadenosine + L-methionine + A + S-adenosyl-L-homocysteine + 2 H(+) | [4Fe-4S] cluster | 432 | Step named |
| Large ribosomal subunit protein bL20 | — | — | — | 118 | Step named |
Origins
How could the ribosome, which makes all proteins and is itself half protein, have come to be?
How it was discovered
- 2000The first high-resolution structures of the ribosomal subunits are published; the peptide bond is found to be formed by ribosomal RNA.Ribas de Pouplana (ed.), The Genetic Code and the Origin of Life, p. 93; Horton et al., Principles of Biochemistry, p. 771
One chapter suggests that the first peptides were made without a ribosome, for example by condensation on mineral surfaces. The same chapter takes the peptidyl transferase centre as the start of the translation machinery.
The chemical mechanism by which the RNA forms the peptide bond is still debated: the first proposal was challenged, and mutation studies of the key residues did not agree with it.
The simplest ribosomes contain about 50 proteins and three ribosomal RNAs totalling about 4,500 nucleotides. Forty-one ribosomal proteins of the minimal set belong to this pathway, and every one is made by ribosomes.
From the books: Ribas de Pouplana (ed.), The Genetic Code and the Origin of Life, p. 93; Horton et al., Principles of Biochemistry, p. 771; Atkins, Gesteland & Cech (eds.), RNA Worlds, p. 143.
The wider question for this part of the cell: origins for building proteins and folding them.
Sources
- Atlas pathway grouping from the VF5 reference-genome system map (Deckert et al. 1998; Braakman & Smith 2014)
Other pathways in this group: Translation interface · RNA maturation · Translation cycle · Protein translocation · Protein turnover · Folding and stabilization · Recycling and rescue · Early folding support · Protein targeting · Ribosome · Protein export · Not yet placed in a pathway