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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Partial digestion with T1 RNAase and chemical modification with kethoxal were used to study stability of two hairpin in the proposed secondary structure of the functionally active MS2 RNA fragment MS2 R(--53 leads to 6), containing the regulatory region of the phage replicase cistron. Analysis of the products obtained after the above treatments showed that T1 RNAase and kethoxal attacked predominantly the guanosine residues in the hairpin b of the MS2 R(--53 leads to 6). This implies that in contrast to the structurally stable hairpin a of the polynucleotide, hairpin b appears to be more labile and may exist under the present experimental conditions in equilibrium with its open form. The data of the competition experiments demonstrated that the kethoxal modified MS2 R(-53 leads to 6) and shorter polynucleotide MS2 R(-53 leads to-11) obtained from MS2 R(-53 leads to 6) after T1 RNAase digestion failed to bind with MS2 coat protein. The relatively unstable hairpin b region in the polynucleotide MS2 R(-53 leads to 6) is suggested to play essential role in the complex formation.
Mol Biol (Mosk)
PMID:[Regulatory region of the MS2 phage RNA replicase cistron. Accesibility of MS2 RNA specific fragment to T1 RNAse digestion and chemical modification with kethoxal]. 10 37

Eight proteins of diverse lengths, functions, and origin, are examined for compositional non-randomness amino acid by amino acid. The proteins investigated are human fibrinopeptide A, guinea pig Insulin, rattlesnake cytochrome c, MS2 phage coat protein, rabbit triosephosphate isomerase, bovine pancreatic deoxyribonuclease A, bovine glutamate dehydrogenase, and Bacillus thermoproteolyticus thermolysin. As a result of this study the experimentally testable hypothesis is put forth that for a large class of proteins the ratio of that fraction of the molecule which exhibits compositional non-randomness to that fraction which does not is on the average, stable about a mean value (estimated as 0.32 plus or minus 0.17) and (nearly) independent of protein length. Stochastic and selective evolutionary forces are viewed as interacting rather than independent phenomena. With respect to amino acid composition, this coupling ameliorates the current controversy over Darwinian vs. non-Darwinian evolution, selectionist vs. neutralist, in favor of neither: Within the context of the quantitative data, the evolution of real proteins is seen as a compromise between the two viewpoints, both important. The compositional fluctuations of the electrically charged amino acids glutamic and aspartic acid, lysine and arginine, are examined in depth for over eighty protein families, both prokaryotic and eukaryotic. For both taxa, each of the acidic amino acids is present in amounts roughly twice that predicted from the genetic code. The presence of an excess of glutamic acid is independent of the presence of an excess of aspartic acid and vice versa.
J Mol Evol 1975 Mar 24
PMID:Deviations from compositional randomness in eukaryotic and prokaryotic proteins: the hypothesis of selective-stochastic stability and a principle of charge conservation. 17 58

The action of snake venom phosphodiesterase on bacteriophage MS2 RNA under conditions of limited hydrolysis has been studied. The content of 5'-mononucleotides released during hydrolysis does not correspond to the calculated one based on the 3'-terminal nucleotide sequence of MS2 RNA. This finding suggests the occurrence of endonucleolytic splits in MS2 RNA with concomitant exonucleolytic digestion of some newly formed fragments. A high molecular weight RNA fraction, comprising unfragmented MS2 RNA with about 5-63'-terminal nucleotides removed is separated by sucrose gradient centrifugation and shown not to differ from the native MS2 RNA in its template function in a cell-free protein synthesizing system. It is demonstrated that template activity, polarity of translation, and nascent peptide chain termination on the MS2 replicase cistron are not affected by the removal of 3'terminal nucleotides of MS2 RNA. Consequently, these nucleotides are unessential in translation of native MS2 RNA.
Mol Biol (Mosk)
PMID:[MS2 RNA hydrolysis by snake venom phosphodiesterase and template properties of RNA produced by limited exonucleolytic action]. 17 65

The nucleic acid binding and unwinding properties of wild-type Escherichia coli ribosomal protein S1 have been compared to those of a mutant form and a large trypsin-resistant fragment, both reported recently [J. Mol. Biol. 127, 41-45 (1979) and J. Biol. Chem. 254, 4309-4312 (1979). The mutant (m1-S1) contains 77% and the fragment (S1-F1) 66% of the polypeptide chain length (approximately 600 amino acid residues) of protein S1. The mutant is active in protein synthesis in vitro; the fragment, although retaining one or more of the functional domains of S1, is inactive in protein synthesis. We find that m1-S1 is is almost as effective as S1 in binding to poly(rU), phage MS2 RNA and simian virus 40 (SV40) DNA, and in unfolding poly(rU) and the helical structures present in MS2 RNA and phi X174 viral DNA. S1-F1, however, binds to poly(rU) and denatured SV40 DNA, but not to MS2 RNA. It unfolds neither poly(rU), nor the residual secondary structure of MS2 RNA or phi X174 viral DNA. Thus, there appears to be a correlation between the loss in ability of S1 to unwind RNA and the loss in its ability to function in protein synthesis.
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PMID:Nucleic acid binding and unfolding properties of ribosomal protein S1 and the derivatives S1-F1 and m1-S1. 23 41

Using an in vitro preparation for protein synthesis, we have studied the effect of the ribosomal protein S1 from Escherichia coli on the synthesis of the coat protein of the RNA-containing phages Qbeta and MS2, on that of an "early" and a "late" enzyme encoded by the DNA containing phage T7, and on that of anthranilate synthetase, an enzyme encoded by the bacterial tryptophan operon. Our results indicate that for the synthesis of these five proteins the presence of S1 is required. From these results we conclude that S1 is an essential protein for the translation of bacterial and bacteriophage messenger RNA.
Mol Gen Genet 1977 May 20
PMID:The effect of the ribosomal protein S1 from Escherichia coli on the synthesis in vitro of bacterial-, DNA phage- and RNA phage proteins. 32 5

The use of triplet code words in E. coli, phiX174, MS2, and rabbit globin was examined. A significant deficiency of purines in the third position of four fold degenerate codons was noted, although its significance is not understood. There has been no consistent selection against uracil in pyrimidine restricted codons. For many amino acids the choice between code words appears random, while for arginine, isoleucine, and probably glycine, distinct biases exist which can be explained in terms of tRNA availability.
J Mol Evol 1978 Feb 21
PMID:Pattern and chance in the use of the genetic code. 34 96

The non-random distribution of degenerate code words in Bacteriophage MS2 RNA can be explained partially by considerations of the stability of the codon-anticodon complex in prokaryotic systems. Supporting this hypothesis we note that wobble codons are positively selected in codons having G and/or C in the first two positions. In contrast, wobble codons are statistically less likely in codons composed of A and U in the first two positions. Analyses of nucleotides adjacent to 5' and 3' ends of codons indicate a nonrandom distribution as well. It is thus likely that some elements of RNA evolution are independent of the structural needs of the RNA itself and of the translated protein product.
J Mol Evol 1978 Dec 29
PMID:Bacteriophage MS2 RNA: a correlation between the stability of the codon: anticodon interaction and the choice of code words. 36 46

A spontaneous streptomycin-resistant Escherichia coli mutant which is temperature-sensitive for suppression of a nonsense codon was studied for its ability to propagate phages T2, T4D, T5, phi K, f2, MS2, R17, Q beta, lambda as well as filamentous phages fl, fd and M13. Of all phages tested, only the growth of Q beta, lambda, and filamentous phages is inhibited in the mutant at 42 degree C. This selective inhibition suggests that, like Q beta, lambda and filamentous phages also require a read-through proten(s) which results from suppression of a termination codon.
Mol Gen Genet 1979 Feb 26
PMID:The requirement of nonsense suppression for the development of several phages. 37 60

The mutant T44(lambda) of Escherichia coli K12, grown in the presence of adenine, develops an increased tolerance to streptomycin. In cultures grown on streptomycin, the ts character (tif) may temporarily be suppressed but, on further transfer, both the temperature-sensitive phenotype and streptomycin tolerance disappear. In a cell-free system, the relative efficiency of translation of MS2 and poly U messenger RNAs was, respectively, 75 and 50% lower in extracts from cultures grown at 37 degrees with adenine than in extracts from 30 degrees cultures. Similar results were obtained when adenine was added in vitro to an extract from a culture grown at 37 degrees in the absence of adenine, using MS2 RNA as messenger. Moreover, the 37 degrees extracts showed a much lower misincorporation of isoleucine into polyphenylalanine in the poly U system. In addition, the Mg++ concentration required for optimal translational acitvity was higher for the 37 degrees than for the 30 degrees extracts. Extracts from a culture grown in L medium at 37 degrees or from a tif-/F'tif+ merodiploid grown at 37 degrees with adenine behaved similarly to that from the 30 degrees culture when poly U was used as messenger RNA. It is suggested that the tif+ gene product may play a regulatory role in ribosomal function and the pleiotropic nature of the tif-1 mutation could be due to impairment of translational activity augmented by elevated temperature or by adenine.
Mol Gen Genet 1976 Aug 10
PMID:Phenotypic instability in a tif-1 Mutant of Escherichia coli. I. Impairment in ribosomal function. 78 26

A compilation of nucleic acid sequences from E. coli and its phages has been analysed for the frequency of occurrence of nearest neighbour base doublets and codons. Several statistically significant deviations from random are found in both doublet and codon frequencies. The deviations in E. coli also appear to occur in lambda and in the coat protein gene of MS2, whereas T4 and other parts of the MS2 genome show different sequence properties. These and other findings are discussed in relation to the hypothesis that rapidity of translation of mRNAs in the E. coli system is dependent on doublet frequency and codon usage patterns.
J Mol Evol 1976 Aug 03
PMID:Doublet frequencies and codon weighting in the DNA of Escherichia coli and its phages. 78 45


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