Evolutionary relationship of Rickettsiae and mitochondria

Emelyanov, V. V.

doi:10.1016/s0014-5793(01)02618-7

Cited by 80 publications

(76 citation statements)

References 50 publications

(124 reference statements)

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“…Notably, no putative MPP-like proteins carrying GRLs were found in the bacterial genomes. Considering the genomic distributions of MPP-like genes described above, and since it is widely accepted that mitochondria originated from the ␣-proteobacterial order Rickettsiales based on phylogenetic analyses comparing the sequences of bacterial and mitochondrial genes (2,9,18,23), MPP is unlikely to have originated from proteins in the host cells of an archaebacterial ancestor and is most likely to have arisen from an RPP-like progenitor in a parasitic bacterium. During the endosymbiotic evolution of mitochondria, the gene encoding the progenitor of MPP, which may be nonessential, similar to ymxG in B. subtilis, could be transferred from the endosymbiont to the host cell.…”

Section: Discussionmentioning

confidence: 99%

A Protein from a Parasitic Microorganism, Rickettsia prowazekii , Can Cleave the Signal Sequences of Proteins Targeting Mitochondria

et al. 2007

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The obligate intracellular parasitic bacteria rickettsiae are more closely related to mitochondria than any other microbes investigated to date. A rickettsial putative peptidase (RPP) was found to resemble the ␣ and ␤ subunits of mitochondrial processing peptidase (MPP), which cleaves the transport signal sequences of mitochondrial preproteins. RPP showed completely conserved zinc-binding and catalytic residues compared with ␤-MPP but barely contained any of the glycine-rich loop region characteristic of ␣-MPP. When the biochemical activity of RPP purified from a recombinant source was analyzed, RPP specifically hydrolyzed basic peptides and presequence peptides with frequent cleavage at their MPP-processing sites. Moreover, RPP appeared to activate yeast ␤-MPP so that it processed preproteins with shorter presequences. Thus, RPP behaves as a bifunctional protein that could act as a basic peptide peptidase and a somewhat regulatory protein for other protein activities in rickettsiae. These are the first biological and enzymological studies to report that a protein from a parasitic microorganism can cleave the signal sequences of proteins targeted to mitochondria.The endosymbiont hypothesis for the origin of mitochondria in eukaryotes is now widely accepted, accompanied by a growing interest in evolution as entire genomic sequences are revealed from various organisms. According to this hypothesis, a free-living bacterium as an organelle progenitor once entered an anaerobic organism, which is thought to be an archaebacterial ancestor, and established a constitutive endosymbiotic relationship with the host cells, mainly to supply ATP (7,11,17). Modern mitochondria originated when the parasitic invader lost most of its own genome and began to depend on nuclearly encoded proteins for its biogenesis, although it retained control of the eukaryotic cell viability via metabolic and apoptotic pathways.Most mitochondrial proteins are encoded in the nucleus and synthesized by cytoplasmic ribosomes as preproteins with Nterminal presequences that are required for targeting to mitochondria (3, 12). These preproteins are unfolded and imported into the mitochondrial matrix across the double membrane through protein translocation machinery comprising a translocase on the outer mitochondrial membrane and a translocase on the inner mitochondrial membrane (20,24,26,27). Finally, the presequences are cleaved by a matrix-located metalloendopeptidase, i.e., mitochondrial processing peptidase (MPP) (10, 13, 16). Overall, this proteolytic processing is involved in maturation of the mitochondrial proteins and is essential for eukaryotic cell viability from unicellular (30) to multicellular (22) organisms. Therefore, the ␣ and ␤ subunits of MPP (␣-and ␤-MPP, respectively) tightly regulate the protease action and specifically cleave the preproteins.The genome sequences of the obligate intracellular parasitic bacteria rickettsiae (the agents that cause typhus) reveal gene profiles strikingly similar to those of mitochondria (2,18,23). Among ...

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Section: Discussionmentioning

confidence: 99%

A Protein from a Parasitic Microorganism, Rickettsia prowazekii , Can Cleave the Signal Sequences of Proteins Targeting Mitochondria

et al. 2007

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“…Although the mitochondria -Rickettsiales connection has been a consistent phylogenetic finding (Viale and Arakaki 1994;Gupta 1995;Sicheritz-Pontén et al 1998;Lang et al 1999), it is still not certain whether the two are sister groups, or whether mitochondria actually branch within Rickettsiales, which is composed of two distinct families, Rickettsiaceae and Anaplasmataceae (Williams et al 2007). In several studies, mitochondria appear to be more closely related to the former family, containing various Rickettsia species, than to the latter, comprising the genera Anaplasma, Ehrlichia, and Wolbachia (Karlin and Brocchieri 2000;Emelyanov 2001aEmelyanov ,b, 2003a.…”

Section: What Do Genetic Genomic and Phylogenomic Data Tell Us Aboumentioning

confidence: 99%

Mitochondrial Evolution

Gray

2012

Cold Spring Harbor Perspectives in Biology

545

309

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“…As the equatorial domain is involved in inter-ring interactions, variations in this domain suggest probable loss of the double-ring formation. It is therefore not surprising that the mitochondrial chaperonins that are derived from Rickettsia (Emelyanov 2001) function as single-ring structures (Nielson et al 1999). Further, the apical domain is responsible for substrate binding and folding.…”

Section: Evolutionary Analysis Of Multiple Groelsmentioning

confidence: 99%

Multiple Gene Duplication and Rapid Evolution in the groEL Gene: Functional Implications

2006

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Abstract. The chaperonins, GroEL and GroES, are present ubiquitously and provide a paradigm in the understanding of assisted protein folding. Due to its essentiality of function, GroEL exhibits high sequence conservation across species. Complete genome sequencing has shown the occurrence of duplicate or multiple copies of groEL genes in bacteria such as Mycobacterium tuberculosis and Corynebacterium glutamicum. Monophyly of each bacterial clade in the phylogenetic tree generated for the GroEL protein suggests a lineage-specific duplication. The duplicated groEL gene in Actinobacteria is not accompanied by the operonic groES despite the presence of upstream regulatory elements. Our analysis suggests that in these bacteria the duplicated groEL genes have undergone rapid evolution and divergence to function in a GroES-independent manner. Evaluation of multiple sequence alignment demonstrates that the duplicated genes have acquired mutations at functionally significant positions including those involved in substrate binding, ATP binding, and GroES binding and those involved in inter-ring and intra-ring interactions. We propose that the duplicate groEL genes in different bacterial clades have evolved independently to meet specific requirements of each clade. We also propose that the groEL gene, although essential and conserved, accumulates nonconservative substitutions to exhibit structural and functional variations.

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Evolutionary relationship of Rickettsiae and mitochondria

Cited by 80 publications

References 50 publications

A Protein from a Parasitic Microorganism, Rickettsia prowazekii , Can Cleave the Signal Sequences of Proteins Targeting Mitochondria

A Protein from a Parasitic Microorganism, Rickettsia prowazekii , Can Cleave the Signal Sequences of Proteins Targeting Mitochondria

Mitochondrial Evolution

Multiple Gene Duplication and Rapid Evolution in the groEL Gene: Functional Implications

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