The biosynthesis of adenosylcobalamin (vitamin B12)

Warren, Martin J.; Raux, Evelyne; Schubert, Heidi; Escalante‐Semerena, Jorge C.

doi:10.1039/b108967f

Cited by 418 publications

(451 citation statements)

References 162 publications

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“…The symbionts appear capable of de novo synthesis of most B vitamins, including the very long vitamin B12 synthesis pathway, as well as a capability for vitamin B12 transport (btuCDF genes identified in the Osedax symbiont Rs1 and the btuC gene in the Rs2 symbiont). It, thus, makes it tempting to speculate that vitamin B12 could be made and transported to the host, which is presumably incapable of its own B12 synthesis, as are all animals (Warren et al, 2002). Similarly, the symbionts are capable of de novo synthesis of all amino acids, except asparagine and tyrosine.…”

Section: Genomic Implications For Intracellular Lifementioning

confidence: 99%

Genomic versatility and functional variation between two dominant heterotrophic symbionts of deep-sea Osedax worms

Goffredi

Zhang

et al. 2013

The ISME Journal

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An unusual symbiosis, first observed at B3000 m depth in the Monterey Submarine Canyon, involves gutless marine polychaetes of the genus Osedax and intracellular endosymbionts belonging to the order Oceanospirillales. Ecologically, these worms and their microbial symbionts have a substantial role in the cycling of carbon from deep-sea whale fall carcasses. Microheterogeneity exists among the Osedax symbionts examined so far, and in the present study the genomes of the two dominant symbionts, Rs1 and Rs2, were sequenced. The genomes revealed heterotrophic versatility in carbon, phosphate and iron uptake, strategies for intracellular survival, evidence for an independent existence, and numerous potential virulence capabilities. The presence of specific permeases and peptidases (of glycine, proline and hydroxyproline), and numerous peptide transporters, suggests the use of degraded proteins, likely originating from collagenous bone matter, by the Osedax symbionts. 13 C tracer experiments confirmed the assimilation of glycine/ proline, as well as monosaccharides, by Osedax. The Rs1 and Rs2 symbionts are genomically distinct in carbon and sulfur metabolism, respiration, and cell wall composition, among others. Differences between Rs1 and Rs2 and phylogenetic analysis of chemotaxis-related genes within individuals of symbiont Rs1 revealed the influence of the relative age of the whale fall environment and support possible local niche adaptation of 'free-living' lifestages. Future genomic examinations of other horizontally-propogated intracellular symbionts will likely enhance our understanding of the contribution of intraspecific symbiont diversity to the ecological diversification of the intact association, as well as the maintenance of host diversity.

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Section: Genomic Implications For Intracellular Lifementioning

confidence: 99%

Genomic versatility and functional variation between two dominant heterotrophic symbionts of deep-sea Osedax worms

Goffredi

Zhang

et al. 2013

The ISME Journal

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“…In total, 20 genes along the first (corrin ring synthesis) and second (lower ligand attachment and rearrangement) parts of the cobalamin biosynthesis pathway were targeted for analysis (Kanehisa and Goto, 2000;Warren et al, 2002). Near-complete cobalamin biosynthesis pathways appear to be present in the Dhc, Methanobacterium and Clostridiaceae classes (Table 4, Supplementary Table S5).…”

Section: Dhc In Anasmentioning

confidence: 99%

Metagenomic analysis of a stable trichloroethene-degrading microbial community

et al. 2012

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Dehalococcoides bacteria are the only organisms known to completely reduce chlorinated ethenes to the harmless product ethene. However, Dehalococcoides dechlorinate these chemicals more effectively and grow more robustly in mixed microbial communities than in isolation. In this study, the phylogenetic composition and gene content of a functionally stable trichloroethene-degrading microbial community was examined using metagenomic sequencing and analysis. For phylogenetic classification, contiguous sequences (contigs) longer than 2500 bp were grouped into classes according to tetranucleotide frequencies and assigned to taxa based on rRNA genes and other phylogenetic marker genes. Classes were identified for Clostridiaceae, Dehalococcoides, Desulfovibrio, Methanobacterium, Methanospirillum, as well as a Spirochete, a Synergistete, and an unknown Deltaproteobacterium. Dehalococcoides contigs were also identified based on sequence similarity to previously sequenced genomes, allowing the identification of 170 kb on contigs shorter than 2500 bp. Examination of metagenome sequences affiliated with Dehalococcoides revealed 406 genes not found in previously sequenced Dehalococcoides genomes, including 9 cobalamin biosynthesis genes related to corrin ring synthesis. This is the first time that a Dehalococcoides strain has been found to possess genes for synthesizing this cofactor critical to reductive dechlorination. Besides Dehalococcoides, several other members of this community appear to have genes for complete or near-complete cobalamin biosynthesis pathways. In all, 17 genes for putative reductive dehalogenases were identified, including 11 novel ones, all associated with Dehalococcoides. Genes for hydrogenase components (271 in total) were widespread, highlighting the importance of hydrogen metabolism in this community. PhyloChip analysis confirmed the stability of this microbial community.

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“…In a more general sense, the carbon‐skeleton rearrangement, proposed for the formation of the isophyllobilanones, 1 and 2 , may be considered an unprecedented variant of the rearrangement of a pinacol 22. This type of rearrangement has also served as mechanistic model for the unique enzymatic21, 23 and chemical24 ring contraction reactions generating corrins from the respective hydroporphyrinoid precursors.…”

mentioning

confidence: 99%

Chlorophyll Breakdown in a Fern—Discovery of Phyllobilin Isomers with a Rearranged Carbon Skeleton

et al. 2018

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All structure‐based information on chlorophyll (Chl) breakdown in the higher plants relies on studies with angiosperms. Herein, the first investigation of a fern is reported, revealing a novel type of Chl catabolites (phyllobilins) in leaves of this large division of the vascular plants, and providing structural insights into an astounding metabolic process of the higher plants that appears to have played a role even in early phases of plant evolution. The tetrapyrrolic Chl catabolites in the cosmopolitan bracken fern were discovered to be phyllobilin isomers with an unprecedented skeleton, proposed to be the striking result of a rearrangement of a hypothetical phyllobilin precursor.

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The biosynthesis of adenosylcobalamin (vitamin B12)

Cited by 418 publications

References 162 publications

Genomic versatility and functional variation between two dominant heterotrophic symbionts of deep-sea Osedax worms

Genomic versatility and functional variation between two dominant heterotrophic symbionts of deep-sea Osedax worms

Metagenomic analysis of a stable trichloroethene-degrading microbial community

Chlorophyll Breakdown in a Fern—Discovery of Phyllobilin Isomers with a Rearranged Carbon Skeleton

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