A Nonhyperthermophilic Common Ancestor to Extant Life Forms

Galtier, Nicolas; Tourasse, Nicolas J.; Gouy, Manolo

doi:10.1126/science.283.5399.220

Cited by 409 publications

(238 citation statements)

References 17 publications

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“…G+C contents of 5S, 16S and 23S rRNAs, and tRNA of all bacteria examined were found to exhibit strong correlations with the optimal growth temperature (OGT), in agreement with previous reports (1,2). The G+C content of 16S rRNA (filled circles in the top panel of Fig.…”

Section: G+c Contents Of 16s Rrnas Versus Temperature-thesupporting

confidence: 78%

“…As G·C pairs held together with three hydrogen bonds are more stable than A·T pairs with two bonds, the G+C contents of thermophilic genomes are expected to be higher. In fact, the G+C content of ribosomal 16S RNA has been reported to be proportional to the bacterial growth temperature (1,2). However, no such simple relationship exists for genomic DNA (3); the average G+C content varies in the wide range from approximately 30% to more than 60% in various bacteria irrespective of the thermophilic/mesophilic types (see Table 1).…”

mentioning

confidence: 99%

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Compositional Changes in RNA, DNA and Proteins for Bacterial Adaptation to Higher and Lower Temperatures

Nakashima

Fukuchi²,

Nishikawa³

2003

Journal of Biochemistry

101

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It is known that in thermophiles the G+C content of ribosomal RNA linearly correlates with growth temperature, while that of genomic DNA does not. Although the G+C contents (singlet) of the genomic DNAs of thermophiles and methophiles do not differ significantly, the dinucleotide (doublet) compositions of the two bacterial groups clearly do. The average amino acid compositions of proteins of the two groups are also distinct. Based on these facts, we here analyzed the DNA and protein compositions of various bacteria in terms of the optimal growth temperature (OGT). Regression analyses of the sequence data for thermophilic, mesophilic and psychrophilic bacteria revealed good linear relationships between OGT and the dinucleotide compositions of DNA, and between OGT and the amino acid compositions of proteins. Together with the above-mentioned linear relationship between ribosomal RNA and OGT, the DNA and protein compositions can be regarded as thermostability measures for RNA, DNA and proteins, covering a wide range of temperatures. Both the DNA and proteins of psychrophiles apparently exhibit characteristics diametrically opposite to those of thermophiles. The physicochemical parameters of dinucleotides suggested that supercoiling of DNA is relevant to its thermostability. Protein stability in thermophiles is realized primarily through global changes that increase charged residues (i.e., Glu, Arg, and Lys) on the molecular surface of all proteins. This kind of global change is attainable through a change in the amino acid composition coupled with alterations in the DNA base composition. The general strategies of thermophiles and psychrophiles for adaptation to higher and lower temperatures, respectively, that are suggested by the present study are discussed.

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Section: G+c Contents Of 16s Rrnas Versus Temperature-thesupporting

confidence: 78%

mentioning

confidence: 99%

Compositional Changes in RNA, DNA and Proteins for Bacterial Adaptation to Higher and Lower Temperatures

Nakashima

Fukuchi²,

Nishikawa³

2003

Journal of Biochemistry

101

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“…Life on earth was only possible as a consequence of parasitism in what was still a molecular world. In fact, life appeared on earth around 4.4-3.8 billion years ago (Chang 1999, Nisbet & Sleep 2001 as a consequence of molecular parasitism and the present day life forms still display relics of these ancient associations in their genomes (Galtier et al 1999, Cavalier-Smith 2001.…”

Section: The Origin and Evolution Of Parasitismmentioning

confidence: 99%

Parasitism, the diversity of life, and paleoparasitology

Araújo

Jansen

Bouchet

et al. 2003

Mem. Inst. Oswaldo Cruz

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“…Phylogenetic methods, for instance, have been used in an attempt to define the (hyper)thermophilic or mesophilic nature of the LUCA by exploiting the correlation between optimal growth temperature and the G+C content of ribosomal RNA and some protein indices (Galtier et al, 1999;Di Giulio, 2001a, 2000b, 2001, 2003a, 2003bBoussau et al, 2008).…”

mentioning

confidence: 99%

“…Subsequently, by phylogenetically reconstructing the ancestral sequences of the LUCA, it was determined whether these were more typical of mesophiles or (hyper)thermophiles (Galtier et al, 1999;Di Giulio, 2000a, 2000b, 2001, 2003a, 2003bBoussau et al, 2008).…”

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confidence: 99%

A methanogen hosted the origin of the genetic code

Giulio

2009

Journal of Theoretical Biology

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A c c e p t e d m a n u s c r i p t A c c e p t e d m a n u s c r i p t 2 AbstractA comparison is made between orthologous proteins from a methanogen (Methanopyrus kandleri) and from a non-methanogen (Pyrococcus abyssi) in order to determine the amino acid substitution pattern. This analysis makes it possible to establish which amino acids are significantly and asymmetrically utilised by these two organisms. A methanophily index (MI) based on this asymmetry makes it possible for any protein to be associated with a numerical value which, when calculated for the same orthologous protein from methanogenic and nonmethanogenic organisms, turns out to have the power to discriminate between these two groups of organisms, even if only for about 20% of the analysed proteins. The MI can also be associated to the genetic code under the assumption that the frequency of synonymous codons specifying the amino acids in the genetic code also reflects the frequency with which amino acids appeared in ancestral proteins. Finally a t test shows that the MI value associated to the genetic code is not different from the mean value of the MI deriving from methanogen proteins, but it differs from the mean MI of non-methanogen proteins. This might indicate that the genetic code evolved in a methanogenic 'organism'.

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A Nonhyperthermophilic Common Ancestor to Extant Life Forms

Cited by 409 publications

References 17 publications

Compositional Changes in RNA, DNA and Proteins for Bacterial Adaptation to Higher and Lower Temperatures

Compositional Changes in RNA, DNA and Proteins for Bacterial Adaptation to Higher and Lower Temperatures

Parasitism, the diversity of life, and paleoparasitology

A methanogen hosted the origin of the genetic code

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