A ribosomal protein is any of the proteins that, in conjunction with rRNA, make up the ribosomal subunits involved in the cellular process of translation. A large part of the knowledge about these organic molecules has come from the study of E. coli ribosomes. All ribosomal proteins have been isolated and many specific antibodies have been produced. These, together with electronic microscopy and the use of certain reactives, have allowed for the determination of the topography of the proteins in the ribosome. E.coli, other bacteria and Archaea have a 30S small subunit and a 50S large subunit, whereas humans and yeasts have a 40S small subunit and a 60S large subunit.[1] Equivalent subunits are frequently numbered differently between bacteria, Archaea, yeasts and humans.[2] More recently, a near-complete (near)atomic picture of the ribosomal proteins is emerging from the latest high-resolution cryo-EM data (including PDB ID: 5AFI).
Conservation of ribosomal proteins
Ribosomal proteins are among the most highly conserved proteins across all life forms.[2] Among the 40 proteins found in various small ribosomal subunits, 15 subunits are universally conserved across pro- and eukaryotes. However, 7 subunits are only found in bacteria (S21, S6, S16, S18, S20, S21, and THX), while 17 subunits are only found in eukaryotes.[2] Typically 22 proteins are found in bacterial 30S subunits and 32 in yeast, human and most likely most other eukaryotic species. 27 (out of 32) proteins of the eukaryotic small ribosomal subunit proteins are also present in archaea (no ribosomal subunit is exclusively found in archaea), confirming that they are more closely related to eukaryotes than to eubacteria.[2]
Among the large ribosomal subunit, 18 proteins are universal, i.e. found in both bacteria and eukaryotes (including archaea). 14 proteins are only found in bacteria, while 27 proteins are only found in eukaryotes (including archaea, which again do not have any archaea-specific proteins).[2]
Essentiality
Despite their high conservation over billions of years of evolution, the absence of several ribosomal proteins in certain species shows that ribosomal subunits have been added and lost over the course of evolution. This is also reflected by the fact that several ribosomal proteins do not appear to be essential when deleted.[3] For instance, in E. coli nine ribosomal proteins (L15, L21, L24, L27, L29, L30, L34, S9, and S17) are nonessential for survival when deleted. Taken together with previous results, 22 of the 54 E. coli ribosomal protein genes can be individually deleted from the genome.[4] Similarly, 16 ribosomal proteins (L1, L9, L15, L22, L23, L28, L29, L32, L33.1, L33.2, L34, L35, L36, S6, S20, and S21) were successfully deleted in Bacillus subtilis. In conjunction with previous reports, 22 ribosomal proteins have been shown to be nonessential in B. subtilis, at least for cell proliferation.[5]
Proteins in E. coli ribosomes
The ribosome of E. coli has about 22 proteins in the small subunit (labelled S1 to S22) and 33 proteins in the large subunit (somewhat counter-intuitively called L1 to L36). All of them are different with three exceptions: one protein is found in both subunits (S20 and L26), L7 and L12 are acetylated and methylated forms of the same protein, and L8 is a complex of L7/L12 and L10. In addition, L31 is known to exist in two forms, the full length at 7.9 kilodaltons (kDa) and fragmented at 7.0 kDa. This is why the number of proteins in a ribosome is of 56. Except for S1 (with a molecular weight of 61.2 kDa), the other proteins range in weight between 4.4 and 29.7 kDa.[6]
Recent 'de novo' proteomics experiments where the authors characterized in vivo ribosome-assembly intermediates and associated assembly factors from wild-type Escherichia coli cells using a general quantitative mass spectrometry (qMS) approach have confirmed the presence of all the known small and large subunit components and have identified a total of 21 known and potentially new ribosome-assembly-factors that co-localise with various ribosomal particles.[7]
Disposition in the small ribosomal subunit
In the small (30S) subunit of E. coli ribosomes, the proteins denoted S4, S7, S8, S15, S17, S20 bind independently to 16S rRNA. After assembly of these primary binding proteins, S5, S6, S9, S12, S13, S16, S18, and S19 bind to the growing ribosome. These proteins also potentiate the addition of S2, S3, S10, S11, S14, and S21. Protein binding to helical junctions is important for initiating the correct tertiary fold of RNA and to organize the overall structure. Nearly all the proteins contain one or more globular domains. Moreover, nearly all contain long extensions that can contact the RNA in far-reaching regions. Additional stabilization results from the proteins' basic residues, as these neutralize the charge repulsion of the RNA backbone. Protein-protein interactions also exist to hold structure together by electrostatic and hydrogen bonding interactions. Theoretical investigations pointed to correlated effects of protein-binding onto binding affinities during the assembly process [8]
Table of E.coli small 30S ribosomal subunit proteins
Assembly of the ribosome in eukaryotes
Ribosomes, which synthesize the proteome of cells, are complex ribonucleoproteins that, in eukaryotes, contain 79–80 proteins and four ribosomal RNAs(rRNAs).
General or specialized chaperones solubilize the ribosomal proteins and facilitate their import into the nucleus. Assembly of the eukaryotic ribosome appears to be driven by the ribosomal proteins in vivo when assembly is also aided by chaperones. Most ribosomal proteins assemble with rRNA co-transcriptionally, becoming associated more stably as assembly proceeds, and the active sites of both subunits are constructed last.[2]
Table of E.coli large 50S ribosomal subunit proteins
Subunit No. |
Subunit name |
E.coli protein |
Pfam family with E.coli protein |
Uniprot accession of E.coli protein |
1 | 50S ribosomal protein L1 | RL1_ ECOLI | PF00687 Ribosomal protein L1p/L10e family | P0A7L0 |
2 | 50S ribosomal protein L2 | RL2_ ECOLI | PF03947 Ribosomal Proteins L2, C-terminal domain | P60422 |
2 | 50S ribosomal protein L2 | RL2_ ECOLI | PF00181 Ribosomal Proteins L2, RNA binding domain | P60422 |
3 | 50S ribosomal protein L3 | RL3_ ECOLI | PF00297 Ribosomal protein L3 | P60438 |
4 | 50S ribosomal protein L4 | RL4_ ECOLI | PF00573 Ribosomal protein L4/L1 family | P60723 |
5 | 50S ribosomal protein L5 | RL5_ ECOLI | PF00281 Ribosomal protein L5 | P62399 |
5 | 50S ribosomal protein L5 | RL5_ ECOLI | PF00673 ribosomal L5P family C-terminus | P62399 |
6 | 50S ribosomal protein L6 | RL6_ ECOLI | PF00347 Ribosomal protein L6 | P0AG55 |
7/12 | 50S ribosomal protein L7/L12 | RL7_ ECOLI | PF16320 Ribosomal protein L7/L12 dimerisation domain | P0A7K2 |
8 | 50S ribosomal protein L7/L12 | RL7_ ECOLI | PF00542 Ribosomal protein L7/L12 C-terminal domain | P0A7K2 |
9 | 50S ribosomal protein L9 | RL9_ ECOLI | PF03948 Ribosomal protein L9, C-terminal domain | P0A7R1 |
9 | 50S ribosomal protein L9 | RL9_ ECOLI | PF01281 Ribosomal protein L9, N-terminal domain | P0A7R1 |
10 | 50S ribosomal protein L10 | RL10_ ECOLI | PF00466 Ribosomal protein L10 | P0A7J3 |
11 | 50S ribosomal protein L11 | RL11_ ECOLI | PF03946 Ribosomal protein L11, N-terminal domain | P0A7J7 |
11 | 50S ribosomal protein L11 | RL11_ ECOLI | PF00298 Ribosomal protein L11, RNA binding domain | P0A7J7 |
13 | 50S ribosomal protein L13 | RL13_ ECOLI | PF00572 Ribosomal protein L13 | P0AA10 |
14 | 50S ribosomal protein L14 | RL14_ ECOLI | PF00238 Ribosomal protein L14p/L23e | P0ADY3 |
15 | 50S ribosomal protein L15 | RL15_ ECOLI | PF00828 Ribosomal protein L18e/L15 | P02413 |
16 | 50S ribosomal protein L16 | RL16_ ECOLI | PF00252 Ribosomal protein L16p/L10e | P0ADY7 |
17 | 50S ribosomal protein L17 | RL17_ ECOLI | PF01196 Ribosomal protein L17 | P0AG44 |
18 | 50S ribosomal protein L18 | RL18_ ECOLI | PF00861 Ribosomal L18p/L5e family | P0C018 |
19 | 50S ribosomal protein L19 | RL19_ ECOLI | PF01245 Ribosomal protein L19 | B1LPB3 |
20 | 50S ribosomal protein L20 | RL20_ ECOLI | PF00453 Ribosomal protein L20 | P0A7L3 |
21 | 50S ribosomal protein L21 | RL21_ ECOLI | PF00829 Ribosomal prokaryotic L21 protein | P0AG48 |
22 | 50S ribosomal protein L22 | RL22_ ECOLI | PF00237 Ribosomal protein L22p/L17e | P61175 |
23 | 50S ribosomal protein L23 | RL23_ ECOLI | PF00276 Ribosomal protein L23 | P0ADZ0 |
24 | 50S ribosomal protein L24 | RL24_ ECOLI | PF00467 KOW motif | P60624 |
25 | 50S ribosomal protein L25 | RL25_ ECOLI | PF01386 Ribosomal L25p family | P68919 |
27 | 50S ribosomal protein L27 | RL27_ ECOLI | PF01016 Ribosomal L27 protein | P0A7M0 |
28 | 50S ribosomal protein L28 | RL28_ ECOLI | PF00830 Ribosomal L28 family | P0A7M2 |
29 | 50S ribosomal protein L29 | RL29_ ECOLI | PF00831 Ribosomal L29 protein | P0A7M6 |
30 | 50S ribosomal protein L30 | RL30_ ECOLI | PF00327 Ribosomal protein L30p/L7e | P0AG51 |
31 | 50S ribosomal protein L31 | RL31_ ECOLI | PF01197 Ribosomal protein L31 | P0A7M9 |
31B | 50S ribosomal protein L31 type B | RL31B_ ECOLI | PF01197 Ribosomal protein L31 | P0A7M9 |
32 | 50S ribosomal protein L32 | RL32_ ECOLI | PF01783 Ribosomal L32p protein family | C4ZS29 |
33 | 50S ribosomal protein L33 | RL33_ ECOLI | PF00471 Ribosomal protein L33 | P0A7N9 |
34 | 50S ribosomal protein L34 | RL34_ ECOLI | PF00468 Ribosomal protein L34 | P0A7P6 |
35 | 50S ribosomal protein L35 | RL35_ ECOLI | PF01632 Ribosomal protein L35 | P0A7Q2 |
36 | 50S ribosomal protein L36 | RL36_ ECOLI | PF00444 Ribosomal protein L36 | P0A7Q7 |
Table of Human small 40S ribosomal subunit proteins
Subunit No. |
Subunit name |
Human protein |
Pfam family with Human protein |
2 | 40S ribosomal protein S2 | RS2_HUMAN | PF03719 Ribosomal protein S5, C-terminal domain |
2 | 40S ribosomal protein S2 | RS2_HUMAN | PF00333 Ribosomal protein S5, N-terminal domain |
3 | 40S ribosomal protein S3 | RS3_HUMAN | PF00189 Ribosomal protein S3, C-terminal domain |
3A | 40S ribosomal protein S3a | RS3A_HUMAN | PF01015 Ribosomal S3Ae family |
4 | 40S ribosomal protein S4, X isoform | RS4X_HUMAN | PF08071 RS4NT (NUC023) domain |
4 | 40S ribosomal protein S4, X isoform | RS4X_HUMAN | PF01479 S4 domain |
4 | 40S ribosomal protein S4, X isoform | RS4X_HUMAN | PF00900 Ribosomal family S4e |
4 | 40S ribosomal protein S4, X isoform | RS4X_HUMAN | PF16121 40S ribosomal protein S4 C-terminus |
4 | 40S ribosomal protein S4, Y isoform 1 | RS4Y1_HUMAN | PF08071 RS4NT (NUC023) domain |
4 | 40S ribosomal protein S4, Y isoform 1 | RS4Y1_HUMAN | PF00900 Ribosomal family S4e |
4 | 40S ribosomal protein S4, Y isoform 1 | RS4Y1_HUMAN | PF16121 40S ribosomal protein S4 C-terminus |
4 | 40S ribosomal protein S4, Y isoform 2 | RS4Y2_HUMAN | PF08071 RS4NT (NUC023) domain |
4 | 40S ribosomal protein S4, Y isoform 2 | RS4Y2_HUMAN | PF00900 Ribosomal family S4e |
4 | 40S ribosomal protein S4, Y isoform 2 | RS4Y2_HUMAN | PF16121 40S ribosomal protein S4 C-terminus |
5 | 40S ribosomal protein S5 | RS5_HUMAN | PF00177 Ribosomal protein S7p/S5e |
6 | 40S ribosomal protein S6 | RS6_HUMAN | PF01092 Ribosomal protein S6e |
7 | 40S ribosomal protein S7 | RS7_HUMAN | PF01251 Ribosomal protein S7e |
8 | 40S ribosomal protein S8 | RS8_HUMAN | PF01201 Ribosomal protein S8e |
9 | 40S ribosomal protein S9 | RS9_HUMAN | PF01479 S4 domain |
9 | 40S ribosomal protein S9 | RS9_HUMAN | PF00163 Ribosomal protein S4/S9 N-terminal domain |
10 | 40S ribosomal protein S10 | RS10_HUMAN | PF03501 Plectin/S10 domain |
11 | 40S ribosomal protein S11 | RS11_HUMAN | PF16205 Ribosomal_S17 N-terminal |
11 | 40S ribosomal protein S11 | RS11_HUMAN | PF00366 Ribosomal protein S17 |
12 | 40S ribosomal protein S12 | RS12_HUMAN | PF01248 Ribosomal protein L7Ae/L30e/S12e/Gadd45 family |
13 | 40S ribosomal protein S13 | RS13_HUMAN | PF08069 Ribosomal S13/S15 N-terminal domain |
13 | 40S ribosomal protein S13 | RS13_HUMAN | PF00312 Ribosomal protein S15 |
14 | 40S ribosomal protein S14 | RS14_HUMAN | PF00411 Ribosomal protein S11 |
15 | 40S ribosomal protein S15 | RS15_HUMAN | PF00203 Ribosomal protein S19 |
15A | 40S ribosomal protein S15a | RS15A_HUMAN | PF00410 Ribosomal protein S8 |
16 | 40S ribosomal protein S16 | RS16_HUMAN | PF00380 Ribosomal protein S9/S16 |
17 | 40S ribosomal protein S17 | RS17_HUMAN | PF00833 Ribosomal S17 |
18 | 40S ribosomal protein S18 | RS18_HUMAN | PF00416 Ribosomal protein S13/S18 |
19 | 40S ribosomal protein S19 | RS19_HUMAN | PF01090 Ribosomal protein S19e |
20 | 40S ribosomal protein S20 | RS20_HUMAN | PF00338 Ribosomal protein S10p/S20e |
21 | 40S ribosomal protein S21 | RS21_HUMAN | PF01249 Ribosomal protein S21e |
23 | 40S ribosomal protein S23 | RS23_HUMAN | PF00164 Ribosomal protein S12/S23 |
24 | 40S ribosomal protein S24 | RS24_HUMAN | PF01282 Ribosomal protein S24e |
25 | 40S ribosomal protein S25 | RS25_HUMAN | PF03297 S25 ribosomal protein |
26 | 40S ribosomal protein S26 | RS26_HUMAN | PF01283 Ribosomal protein S26e |
27 | 40S ribosomal protein S27 | RS27_HUMAN | PF01667 Ribosomal protein S27 |
28 | 40S ribosomal protein S28 | RS28_HUMAN | PF01200 Ribosomal protein S28e |
29 | 40S ribosomal protein S29 | RS29_HUMAN | PF00253 Ribosomal protein S14p/S29e |
30 | 40S ribosomal protein S30 | RS30_HUMAN | PF04758 Ribosomal protein S30 |
A | 40S ribosomal protein SA | RSSA_HUMAN | PF16122 40S ribosomal protein SA C-terminus |
A | 40S ribosomal protein SA | RSSA_HUMAN | PF00318 Ribosomal protein S2 |
Table of Human large 60S ribosomal subunit proteins
See also
References
- ↑ Rodnina MV, Wintermeyer W (Apr 2011). "The ribosome as a molecular machine: the mechanism of tRNA-mRNA movement in translocation". Biochemical Society Transactions 39 (2): 658–62. doi:10.1042/BST0390658. PMID 21428957.
- 1 2 3 4 5 6 Ban N, Beckmann R, Cate JH, Dinman JD, Dragon F, Ellis SR, Lafontaine DL, Lindahl L, Liljas A, Lipton JM, McAlear MA, Moore PB, Noller HF, Ortega J, Panse VG, Ramakrishnan V, Spahn CM, Steitz TA, Tchorzewski M, Tollervey D, Warren AJ, Williamson JR, Wilson D, Yonath A, Yusupov M (Feb 2014). "A new system for naming ribosomal proteins". Current Opinion in Structural Biology 24: 165–9. doi:10.1016/j.sbi.2014.01.002. PMC 4358319. PMID 24524803.
- ↑ Gao, F; Luo, H; Zhang, C. T.; Zhang, R (2015). "Gene Essentiality Analysis Based on DEG 10, an Updated Database of Essential Genes". Gene Essentiality. Methods in Molecular Biology 1279. pp. 219–33. doi:10.1007/978-1-4939-2398-4_14. ISBN 978-1-4939-2397-7. PMID 25636622.
- ↑ Shoji S, Dambacher CM, Shajani Z, Williamson JR, Schultz PG (2011). "Systematic chromosomal deletion of bacterial ribosomal protein genes". J. Mol. Biol. 413 (4): 751–61. doi:10.1016/j.jmb.2011.09.004. PMC 3694390. PMID 21945294.
- ↑ Akanuma G, Nanamiya H, Natori Y, Yano K, Suzuki S, Omata S, Ishizuka M, Sekine Y, Kawamura F (2012). "Inactivation of ribosomal protein genes in Bacillus subtilis reveals importance of each ribosomal protein for cell proliferation and cell differentiation". J. Bacteriol. 194 (22): 6282–91. doi:10.1128/JB.01544-12. PMC 3486396. PMID 23002217.
- ↑ Arnold RJ, Reilly JP (Apr 1999). "Observation of Escherichia coli ribosomal proteins and their posttranslational modifications by mass spectrometry". Analytical Biochemistry 269 (1): 105–12. doi:10.1006/abio.1998.3077. PMID 10094780.
- ↑ Chen SS, Williamson JR (Feb 2013). "Characterization of the ribosome biogenesis landscape in E. coli using quantitative mass spectrometry". Journal of Molecular Biology 425 (4): 767–79. doi:10.1016/j.jmb.2012.11.040. PMC 3568210. PMID 23228329.
- ↑ Hamacher K, Trylska J, McCammon JA (Feb 2006). "Dependency map of proteins in the small ribosomal subunit". PLoS Computational Biology 2 (2): e10. doi:10.1371/journal.pcbi.0020010. PMC 1364506. PMID 16485038.
Further reading
- Korobeinikova AV, Garber MB, Gongadze GM (Jun 2012). "Ribosomal proteins: structure, function, and evolution". Biochemistry (Moscow) 77 (6): 562–74. doi:10.1134/S0006297912060028. PMID 22817455.
- Ban N, Beckmann R, Cate JH, Dinman JD, Dragon F, Ellis SR, Lafontaine DL, Lindahl L, Liljas A, Lipton JM, McAlear MA, Moore PB, Noller HF, Ortega J, Panse VG, Ramakrishnan V, Spahn CM, Steitz TA, Tchorzewski M, Tollervey D, Warren AJ, Williamson JR, Wilson D, Yonath A, Yusupov M (Feb 2014). "A new system for naming ribosomal proteins". Current Opinion in Structural Biology 24: 165–9. doi:10.1016/j.sbi.2014.01.002. PMC 4358319. PMID 24524803.
External links