Ribosomal proteins. Secondary structure of individual ribosomal proteins of <i>E. coli</i> studied by circular dichroism

Dzionara, M.

doi:10.1016/0014-5793(70)80262-9

Cited by 42 publications

(14 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…So far, infrared and circular dichroism spectra have provided the idea that a certain amount of both a-helices and/3-structures are present [22][23][24] ; for instance, in a recent CD-study on some 30S proteins ($4, $6, $7, and $8) 25-30% a-helices and about 20%/3-structures were reported [24]. Such a mixture of different secondary structures also seem to exist in the present proteins [15,17], and our X-ray data do not contradict these findings.…”

Section: Resultsmentioning

confidence: 99%

Small‐angle X‐ray scattering study of the 5S RNA binding proteins L18 and L25 from Escherichia coli ribosomes

Österberg

Sjöberg

1976

FEBS Letters

View full text Add to dashboard Cite

Section: Resultsmentioning

confidence: 99%

Small‐angle X‐ray scattering study of the 5S RNA binding proteins L18 and L25 from Escherichia coli ribosomes

Österberg

Sjöberg

1976

FEBS Letters

View full text Add to dashboard Cite

“…(15). In addition, Dzionara (14) has shown that most of the other ribosomal proteins have an a-helical content between 20 and 35%. Fig.…”

Section: Methodsmentioning

confidence: 99%

The Effect of Various Nucleotides on the Helical Nature of a Ribosomal Protein(s) from Escherichia coli

Brot

Boublík

Yamasaki

et al. 1972

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

In the presence of GTP or GDP, there is a decrease in the circular dichroic absorption of ribosomal proteins L7 and L12 at 221-222 nm, suggesting that these nucleotides influence the helical content of these proteins.All of the proteins from the 30S and 50S ribosomal subunits of Escherichia coli have been purified to homogeneity (1-5), although little is known about the function of these proteins in polypeptide synthesis. Recently Hamel et al. (6) and our laboratory (7) reported the isolation of a ribosomal protein fraction from E. coli that is required for the function of both elongation factors Tu (EF-Tu) and G (EF-G). We concluded-on the basis of disc gel electrophoresis at pH 4.5, amino-acid analysis, and molecular weight-that the purified material contains two proteins identical to the Al and A2 proteins described by M6ller et at. (8), and proteins L7 and L,2 isolated by Wittmann and his coworkers (9-11). The latter designations will be used in this report. These two proteins appear identical by all physical parameters measured. Thus, they are both acidic, have molecular weights of about 13,000, have a high a-helical content, similar amino-acid analysis, and are immunologically crossreactive. The only difference appears to be that L7 contains an N-acetylated amino-terminal serine, whereas in L12 the N-terminal serine is unblocked (12).In view of the high helicity of proteins L7 and L12, and the fact that their presence on the ribosome is required for the GTP-dependent EF-Tu and EF-G reactions in protein synthesis, it seemed of interest to investigate whether the helical nature of these proteins could be altered in any way. For example, one could speculate that these helical proteins, by virtue of their ability to undergo a reversible conformational change, may be involved in movement of the ribosome along messenger RNA. The present report describes the effect of various nucleotides on the circular dichroism (CD) spectra of a mixture of proteins L7 and L12. MATERIALS AND METHODSE. coli ribosomes were isolated and washed in a buffered 1 M NH4C1 solution (13). These salt-washed ribosomes were treated with 40% ethanol in the presence of 1 M NH4Cl (6, 7), and the ribosomal proteins L7 and L12 were purified together (7) from the ethanolic supernatant. The CD spectra were performed at room temperature in a 0.01-cm cell on a Cary 61 recording spectropolarimeter. The standard mixture contained 10 mM (each) of Tris HCl buffer (pH 7.4), MgC12, NH4C1, and, where indicated, the following were added (final concentrations): 0.7 mg/ml of a mixture of ribosomal proteins L7 and L12, 0.7 mg/ml of EF-G, and 2.5 mM or 4 mM nucleotide. The data are expressed as the mean residue ellipticity (0) (deg. cm2/dmol), and are not corrected for the refractive index of the solvent. A value of 117 was used as the mean residue weight of the ribosomal proteins, and 127 for the mean residue weight of EF-G.RESULTS AND DISCUSSION Fig. 1 shows the CD spectra of the ribosomal proteins and of EF-G. The spectrum of the mixture of L7 and L12...

show abstract

“…(i) They are acidic, while the majority of ribosomal proteins are basic (22)(23)(24). (ii) Their amino-acid compositions are distinctive: each contains e-N-monomethyllysine and about 25 mol % alanine (22)(23)(24).…”

Section: Methodsmentioning

confidence: 99%

“…(ii) Their amino-acid compositions are distinctive: each contains e-N-monomethyllysine and about 25 mol % alanine (22)(23)(24). (iii) Compared to other ribosomal proteins, they have a high a-helix content (about 50-60%) (24,25). (iv) Proteins L7 and L12 are immunologically identical (18) and, except for an N-acetylblocked terminal serine in L7, they appear to be identical in sequence (26,27)'".…”

Section: Methodsmentioning

confidence: 99%

Identity of the Ribosomal Proteins Involved in the Interaction with Elongation Factor G

Highland

Bodley

Gordon

et al. 1973

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

Rabbit antibodies produced against 50 of the 55 individually purified ribosomal proteins of Escherichia coli were tested for their ability to interfere with the formation of the ribosomceEF-G-GDP complex. Only antibodies produced against proteins L7 and L12 inhibited complex formation, and they did so completely.These two proteins were previously shown to be immunologically indistinguishable and necessary for the interaction between ribosomes and EF-G. The present data are consistent with the view that the interaction between ribosomes and EF-G that results in GTP hydrolysis occurs on, and is limited to, proteins L7 and L12 on the surface of the 50S ribosomal subunit.Establishment of the structure-function relationships of ribosomes and the mechanisms of GTP involvement in ribosome function are two of the major goals in defining the process of translation of the genetic code (for recent reviews, see refs. 3 and 4).Elucidation of ribosomal structure-function relationships has been thwarted by the complexity and cooperativity of ribosomal structure (the ribosome is composed of more than 50 distinct macromolecules), as well as the complexities of its functions. The availability of antibodies produced against individually purified ribosomal proteins now provides a potentially powerful tool with which to investigate the functional topology of ribosomes. Already, experiments involving the use of antibodies have successfully defined the specific ribosomal proteins involved in streptomycin and spectinomycin binding (5)**,tt, yielded information on the identity of the ribosomal proteins that bind ribosomal RNA (6, 7), and implicated proteins L7 and L12 in the interaction between ribosomes and EF-G (8).Similarly, elucidation of the roles of GTP in ribosome function has been hampered by the complexities of the re-* This is paper no. XLII in the series "Ribosomal Proteins" and paper no. XIII in the series "Studies on Translocation." The preceding papers in these series are refs. 1 and 2, respectively.

show abstract

Ribosomal proteins. Secondary structure of individual ribosomal proteins of E. coli studied by circular dichroism

Cited by 42 publications

References 15 publications

Small‐angle X‐ray scattering study of the 5S RNA binding proteins L18 and L25 from Escherichia coli ribosomes

Small‐angle X‐ray scattering study of the 5S RNA binding proteins L18 and L25 from Escherichia coli ribosomes

The Effect of Various Nucleotides on the Helical Nature of a Ribosomal Protein(s) from Escherichia coli

Identity of the Ribosomal Proteins Involved in the Interaction with Elongation Factor G

Contact Info

Product

Resources

About