Comparison of protein sequences of hsp70

Archaea are now recognized as one of two main areas of prokaryotes [1, 2]. Most of the genes that show

archaea, distinct from bacteria to transfer information processes such as DNA replication, transcription and translation [3, 4]. Of these, DNA replication machinery is very different between the two domains [5]. In terms of transcription, the basic units of RNA polymerase (s) are the same as in

Bacteria and archaea,

archaea but also contains several smaller units and some transcription factors not found in bacteria. Most of the components of translation machinery, which includes various rRNA, r-proteins, the main factors, elongation, and various amino acids, enzymes, and tRNA charging, etc., usually common to both bacteria and archaea [3, 6] . In addition, Mr. proteins in archaea >> << are also located in operonov similar to that observed in bacteria. But

archaea differ from bacteria in some unique R-proteins and initiation factors of translation. Archaea differ from most bacteria in their cell membrane and cell wall composition [1, 2, 7]. (Fig. 1)

Fig. 1 Comparison between the shell membrane prokaryotes. However, besides these differences,

archaea are widely similar to bacteria. Most of the metabolic pathways that make up the vast majority of all the repertoire of genes of an organism, are common between

archaea and bacteria [8]. In terms of their structure cells

archaea do not differ from gram-positive bacteria. In prokaryotes, only these two groups of organisms are buy strattera limited by a lipid membrane unit [9-11], and they usually contain thick sakkulyusa different chemical composition [12]. Some

archaea also show positive staining gram-negative and some of them (namely, Thermoplasma), similar to certain Gram-positive bacteria (eg mycoplasma) do not contain cell wall [2]. The similarity of archaea and bacteria spread to many other characteristics, including cell size significantly smaller (100-1000 times) than in eukaryotic cells lack nuclei, cytoskeleton, histones, spliceosomal introns, circular organization of their genomes, the organization of genes in the operon, the presence of 70S ribosomes, etc. [13] Kunyn et al. [8] showed that about 63% of genes in

M. janaschii in other bacteria, whereas only 5% of them clearly with Eukarya. Although about 1/3 of the total genes in the archaea >> << are unique (ie not see the similarity with other organisms), the same is true for most other prokaryotic genomes. Rice. 2 Comparison of protein sequences Hsp70 >> << In phylogenetic trees based on several different proteins archaea species show polyfyletycheskoho branching in gram-positive bacteria. [14-16] If we consider only prokaryotycheskyh homologues, the phylogenetic tree for the majority of proteins showed that archaea

more closely related to gram-positive bacteria (eg, monoderm bacteria, which include

Thermotoga) than Gram-negative bacteria (unpublished results). [9] evidence for closer relations between

archaea and gram-positive bacteria compared to gram-negative bacteria, also provided a number of known sequences of signature (ie, 21-23 aa INDEL in Hsp70 (Fig. 2) and 26 aa INDEL in GS I), which are usually clearly divides these two groups of prokaryotes. [9, 17]

Fig. Image 3 Kendler in universal ancestors

Questions can now question how these differences between archaea and bacteria possibly originated and how these two groups relate to each other? Since most genes that show

archaea must be separated from the bacteria to processes of information transfer, and these processes are of fundamental importance, it is suggested that these differences arose in the universal ancestors to the separation of these two areas. Vouz and Kendler [18, 19] believe that these two areas as well as eukaryotic cells evolved from pre-mobile community, which contain different types of genes in the process that led to the fixing of a specific subset of genes in the ancestors of these areas. These previous cellular entities posited, have a stable genealogical or chromosomes, and no typical cell membrane, which allows unlimited lateral translation of genes [18, 19]. Under these proposals all the differences between the

archaea and bacteria arose in an earlier stage of cell Darwin without money, but they offer no reason as why there are differences between the two groups emerged or developed. Cavalier-Smith [20] suggested the possibility

archaea development of gram-positive bacteria, as adaptation to hyperthermophily or increased acidity, but it does not explain how the various differences in the genes, information transfer that distinguish

archaea from bacteria emerged. Gupta [9, 10] proposed an alternative proposal to explain the striking similarity between archaea and saw the gram-positive bacteria, the cell structures in different phylogeny of genes and several other important observations. An important characteristic of archaea >> << that they are resistant to broad spectrum antibiotics, which are mainly produced by gram-positive bacteria [9]. These antibiotics affect genes (namely transmission of information or processes and synthesis of cell wall and membrane components), which primarily provide

archaea from bacteria. These observations are central to understanding the origin of Archean >>. If << differences that characterize

archaea from bacteria developed in the pre-cellular phase

it is difficult to understand how archaea evolved resistance to various antibiotics produced gram-positive bacteria [21, 22]. It appears also that too many matches that the majority of genes that distinguish

archaea from bacteria provide the main purpose of these antibiotics. In the table above describes the sites of action of antibiotics. The majority of known antibiotics produced by gram-positive bacteria

To explain these observations, Gupta suggested that the first groups of prokaryotes, which evolved, were associated with gram-positive bacteria [9, 10, 21, 22]. Features that distinguish

archaea from bacteria and not develop independently of each other on stage precellular derived from gram-positive bacteria, in response to antibiotic selection pressure. In one likely scenario, after a group of gram-positive bacteria designed to conduct various kinds of antibiotics to survive in this highly selective environment of some bacteria has undergone significant changes in genes that are to these antibiotics. The changes leading to resistance were different species, including mutations, insertion / deletion, not homologous recombination, and gene-replacement targets with non orthological genes. The long and consistent elections in various antibiotics containing environment led to the eventual development of sustainable strain, which has undergone significant changes in many genes that were the objects of these antibiotics and this strain is a common ancestor of modern

archaea [9, 10, 21, 22]. The evolution of archaea >> << in response to antibiotic selection also provides a plausible explanation for their adaptation to harsh environments such as high temperature, high salt or high temperature and acidity, etc. It is assumed that these devices were defensive strategies to find niches that are hostile to antibiotics of organisms [9, 10, 21, 22]. Thus, unlike other proposals, this proposal can logically explain the evolution of the most distinctive characteristics of Archaea

known groups of bacteria normal evolutionary mechanisms, without attributing such differences in the unusual properties of the universal ancestor. Because these differences between

archaea and bacteria have evolved at a very early stage in the history of prokaryotes (Fig. 4), archaea

appear different from bacteria in phylogenetic trees based on these characteristics. Interestingly, in this context that the analysis of genomic sequences on the lake and his colleagues argue that the root of the tree of life does not lie either in archaea [23] or Gram-negative (diderm) bacteria [24]. .