Structural studies of ribosomes

Liljas, Anders

doi:10.1016/0079-6107(82)90013-x

Cited by 160 publications

(65 citation statements)

References 361 publications

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“…The same amino acids Val-Ala-Val-Ala-Ala are deleted in the rplL26.5 mutant. Both deletions are located around position 40 in the hinge region, which connects the N-terminal and the C-terminal domain of the L7/L12 protein [43]. The point mutations are located in the C-terminal domain of the protein since the rplL518 mutant is changed at position 74 where a Gly is replaced by an Asp.…”

Section: Determination Of the Amino Acid Alterations In L7/l12 Mutantmentioning

confidence: 99%

Primary structures of mutationally altered ribosomal protein L7/L12 and their effects on cellular growth and translational accuracy

1986

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The amino acid sequences of mutationally altered ribosomal protein L7/L12 from four different rplL mutants of Escherichia coli were determined and correlated with some features of the mutant ribosomes. Two of the rplL mutations are deletions around position 40, which give rise to a shortened hinge region between the two domains of L7/L12. The other two mutants harbor point mutations at position 74 (Gly+Asp) or at position 82 (Glu+Lys), which are in or close to an evolutionarily conserved sequence in the C-terminal domain. The two latter mutations are associated with decreased rates of growth and translational elongation. All four mutants show increased nonsense codon read-through in vivo. Ribosomes from one of the deletion mutants show clearly increased missense error rates in vitro.Some mutationally altered ribosomal proteins affect translational accuracy both in vivo and in vitro. The best characterized examples of far are mutants with changed S12 (rpsL), which show a more accurate phenotype, and with altered S4 (rpsD), which are less accurate during translation [l -81. These mutants [9, 101 are primarily defective in translational proof-reading step(s) [ll -151. Recent observations show that S5 (rpsE) mutations, which are associated with a ribosomal ambiguity (Ram) phenotype in vivo and in vitro, produce ribosomes which have a decreased proof-reading intensity [16,17,441. Furthermore, mutations in rpsQ (S17) and in rplF (L6) might give a more accurate translation but such mutants are not so well characterized as those affecting S4 and S12 [18, 191. Recently ribosomal protein L7/L12 was shown to be involved in the maintenance of translational accuracy. It was found that some mutations in the gene coding for this protein (rplL) increase the translational error rates both in vivo and in vitro. Furthermore, the increased error level, characteristic of the mutant ribosomes containing altered forms of L7/L12, can be correlated with a decreased proof-reading efficiency. The increased translational misreading in vivo is reversed by the introduction of an rpsL allele, which gives a Str-R phenotype. Therefore it appears that some mutants with altered L7/L12 in many respects are similar to S4 and S5 mutants [7, 9, 20, 441 in that they both increase error frequencies and suppress streptomycin-dependent phenotypes.In the present investigation we have purified the L7/L12 protein [21] from four different rplL mutants and localized the corresponding alterations by determining their amino acid sequences. In addition, we describe the effects of these mutational alterations on translation rates both in vivo MATERIALS AND METHODS Construction of strainsThe E. coli K12 strains used in this study are listed in Table 1. The rplL159, rplL265 and rplL564 alleles were introduced by PI -mediated cotransduction with argE+ into UY128 and UD132 followed by screening for rifampicin sensitivity (Rif-S) as described elsewhere [20]. Strain VT564 was used as the donor of rplL564.Construction of the rplL518 derivatives UY258 and UY278 was...

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Section: Determination Of the Amino Acid Alterations In L7/l12 Mutantmentioning

confidence: 99%

Primary structures of mutationally altered ribosomal protein L7/L12 and their effects on cellular growth and translational accuracy

1986

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“…It displays a clearly functional activity and is involved in all translation factor-dependent reactions of the ribosome (for review see [3]). From physico-chemical and functional studies the structural model of the L7/L12 can be described as a two domain dimeric protein, where the double-helical domain comprises the Nterminal parts of its amino acid sequence and the C-terminal (residues 52-120) parts are globules [4].…”

Section: Introductionmentioning

confidence: 99%

“…Various arrangements of the subunits in the L7/L12 dimer have been proposed: with antiparallel (head-to-tail [4]) and parallel orientations (reviewed in [3]). A flexible interdomain (hinge) region including 38-50 residues was established by NMR studies [9].…”

Section: Introductionmentioning

confidence: 99%

The first 37 residues are sufficient for dimerization of ribosomal L7/L12 protein

1995

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“…The acidic L7/L!2 protein (120 amino acids) and its analog are found in ribosomes of all organisms and play an important role in protein biosynthesis [1,2]. The depletion of L7/Ll2 from ribosomes inh~.bits protein synthesis and decreases elongation factor activity [3][4][5][6][7].…”

Section: Introductionmentioning

confidence: 99%

The length of the interdomain region of the L7/L12 protein is important for its function

1992

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Structural studies of ribosomes

Cited by 160 publications

References 361 publications

Primary structures of mutationally altered ribosomal protein L7/L12 and their effects on cellular growth and translational accuracy

Primary structures of mutationally altered ribosomal protein L7/L12 and their effects on cellular growth and translational accuracy

The first 37 residues are sufficient for dimerization of ribosomal L7/L12 protein

The length of the interdomain region of the L7/L12 protein is important for its function

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