On an Early Gene for Membrane-Integral Inorganic Pyrophosphatase in the Genome of an Apparently Pre-LUCA Extremophile, the Archaeon Candidatus Korarchaeum cryptofilum
| Autor: | Bengt Persson, Herrick Baltscheffsky |
|---|---|
| Rok vydání: | 2014 |
| Předmět: |
Amino Acid Motifs
Molecular Sequence Data Genome chemistry.chemical_compound Genome Archaeal Crenarchaeota Genetics Extremophile Amino Acid Sequence Molecular Biology Gene Phylogeny Ecology Evolution Behavior and Systematics chemistry.chemical_classification Pyrophosphatase Inorganic pyrophosphatase biology biology.organism_classification Archaea Biological Evolution Amino acid Inorganic Pyrophosphatase chemistry Biochemistry Euryarchaeota Sequence Alignment |
| Zdroj: | Journal of Molecular Evolution. 78:140-147 |
| ISSN: | 1432-1432 0022-2844 |
| DOI: | 10.1007/s00239-014-9610-7 |
| Popis: | A gene for membrane-integral inorganic pyrophosphatase (miPPase) was found in the composite genome of the extremophile archaeon Candidatus Korarchaeum cryptofilum (CKc). This korarchaeal genome shows unusual partial similarity to both major archaeal phyla Crenarchaeota and Euryarchaeota. Thus this Korarchaeote might have retained features that represent an ancestral archaeal form, existing before the occurrence of the evolutionary bifurcation into Crenarchaeota and Euryarchaeota. In addition, CKc lacks five genes that are common to early genomes at the LUCA border. These two properties independently suggest a pre-LUCA evolutionary position of this extremophile. Our finding of the miPPase gene in the CKc genome points to a role for the enzyme in the energy conversion of this very early archaeon. The structural features of its miPPase indicate that it can pump protons through membranes. An miPPase from the extremophile bacterium Caldicellulosiruptor saccharolyticus also has a sequence indicating a proton pump. Recent analysis of the three-dimensional structure of the miPPase from Vigna radiata has resulted in the recognition of a strongly acidic substrate (orthophosphate: Pi, pyrophosphate: PPi) binding pocket, containing 11 Asp and one Glu residues. Asp (aspartic acid) is an evolutionarily very early proteinaceous amino acid as compared to the later appearing Glu (glutamic acid). All the Asp residues are conserved in the miPPase of CKc, V. radiata and other miPPases. The high proportion of Asp, as compared to Glu, seems to strengthen our argument that biological energy conversion with binding and activities of orthophosphate (Pi) and energy-rich pyrophosphate (PPi) in connection with the origin and early evolution of life may have started with similar or even more primitive acidic peptide funnels and/or pockets. |
| Databáze: | OpenAIRE |
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