Aerobic synthesis of vitamin B12: ring contraction and cobalt chelation.

@article{Heldt2005AerobicSO,
  title={Aerobic synthesis of vitamin B12: ring contraction and cobalt chelation.},
  author={D. Heldt and A. Lawrence and M. Lindenmeyer and E. Deery and P. Heathcote and S. Rigby and M. Warren},
  journal={Biochemical Society transactions},
  year={2005},
  volume={33 Pt 4},
  pages={
          815-9
        }
}
The aerobic biosynthetic pathway for vitamin B12 (cobalamin) biosynthesis is reviewed. Particular attention is focused on the ring contraction process, whereby an integral carbon atom of the tetrapyrrole-derived macrocycle is removed. Previous work had established that this chemically demanding step is facilitated by the action of a mono-oxygenase called CobG, which generates a hydroxy lactone intermediate. This mono-oxygenase contains both a non-haem iron and an Fe-S centre, but little… Expand
The requirement for cobalt in vitamin B12: A paradigm for protein metalation☆
TLDR
The partitioning of cobalt for cobalamin biosynthesis exemplifies how cells assist metalation and is investigated to investigate why cobalt is paired specifically with the corrin ring, how Cobalt is inserted during the biosynthetic process, how cobALT is made available within the cell and explore the cellular control of cobALT and cobalam levels. Expand
Anaerobic synthesis of vitamin B12: characterization of the early steps in the pathway.
TLDR
Structural studies are being used to provide insights into how aspects of this highly complex biosynthetic pathway may have evolved and some recent advances in assigning functions to the enzymes of the anaerobic pathway are being made. Expand
Vitamin B(12) metabolism in Mycobacterium tuberculosis.
TLDR
Observations suggest that M. tuberculosis has the capacity to regulate core metabolic functions according to B12 availability - whether acquired via endogenous synthesis or through uptake from the host environment - and imply that there is a role for vitamin B12 in pathogenesis, which remains poorly understood. Expand
Metabolic engineering of Escherichia coli for de novo biosynthesis of vitamin B12
TLDR
An Escherichia coli strain is generated that produces vitamin B12 via an engineered de novo aerobic biosynthetic pathway using 28 pathway synthesis genes from several bacteria including R. capsulatus to E. coli and, using metabolic engineering and optimised fermentation conditions, achieves high yields. Expand
Metabolic engineering of Escherichia coli for de novo biosynthesis of vitamin B12
TLDR
An Escherichia coli strain is generated that produces vitamin B12 via an engineered de novo aerobic biosynthetic pathway and it is suggested that the biosynthetical steps from co(II)byrinic acid a,c-diamide to adocobalamin are the same in both the aerobic and anaerobic pathways. Expand
Comparative genomic analyses of nickel, cobalt and vitamin B12 utilization
TLDR
Investigation of environmental and other conditions and identity of organisms that show dependence on Ni or Co revealed that host-associated organisms (particularly obligate intracellular parasites and endosymbionts) have a tendency for loss of Ni/Co utilization. Expand
Crystal structures of CbiL, a methyltransferase involved in anaerobic vitamin B12 biosynthesis, and CbiL in complex with S‐adenosylhomocysteine − implications for the reaction mechanism
TLDR
A catalytic mechanism is proposed: the conserved Tyr226 residue in CbiL catalyzes the direct transfer of a methyl group from S‐adenosylmethionine to the substrate through an SN2‐like mechanism. Expand
Synthesis of cobalamin analogues using enzymatic and chemical modification methods, and subsequent identification of cobalamin localisation in a variety of organisms
Cobalamin, also known as vitamin B12, is an essential nutrient for many different organisms including mammals, fish, birds, nematodes, and a variety of bacteria. However, cobalamin is onlyExpand
Calculating metalation in cells reveals CobW acquires CoII for vitamin B12 biosynthesis while related proteins prefer ZnII
TLDR
A metalation-calculator is developed which accounts for inter-metal competition and changing metal-availabilities inside cells, and reveals that related GTPases with comparable ZnII affinities to CobW, preferentially acquire Zn II due to their relatively weaker CoII Affinities. Expand
Heterologous expression of cobalamin dependent class-III enzymes
TLDR
A comparative study of the heterologous expression strains Bacillus megaterium, Escherichia coli HMS174(DE3), Shimwellia blattae and a commercial strain of Vibrio natrigenes for cobalamin class-III dependent enzymes expression concludes that co-expression of BtuB in E. coli presents an appropriate balance between cofactor incorporation and protein yield in both cases. Expand
...
1
2
3
4
5
...

References

SHOWING 1-10 OF 28 REFERENCES
Identification and Characterization of a Novel Vitamin B12 (Cobalamin) Biosynthetic Enzyme (CobZ) from Rhodobacter capsulatus, Containing Flavin, Heme, and Fe-S Cofactors*
TLDR
Recombinant overproduction of Orf663, now renamed CobZ, allowed the characterization of a novel cofactor-rich protein, housing two Fe-S centers, a flavin, and a heme group, which like B12 itself is a modified tetrapyrrole. Expand
Anaerobic synthesis of vitamin B12: characterization of the early steps in the pathway.
TLDR
Structural studies are being used to provide insights into how aspects of this highly complex biosynthetic pathway may have evolved and some recent advances in assigning functions to the enzymes of the anaerobic pathway are being made. Expand
Biosynthesis of cobalamin (vitamin B12): a bacterial conundrum
Abstract. The biosynthesis of cobalamin (vitamin B12) is described, revealing how the concerted action of around 30 enzyme-mediated steps results in the synthesis of one of Nature's most structurallyExpand
Cobalamin (coenzyme B12): synthesis and biological significance.
TLDR
This review examines deoxyadenosylcobalamin (Ado-B12) biosynthesis, transport, use, and uneven distribution among living forms and suggests that the B12 synthetic pathway may have evolved to allow anaerobic fermentation of small molecules in the absence of an external electron acceptor. Expand
Vitamin B12: How the Problem of Its Biosynthesis Was Solved
Vitamin B12 is an essential vitamin for human health, and lack of it leads to pernicious anemia. This biological activity has attracted intense interest for some time; in addition, the complexExpand
Magnesium-dependent ATPase Activity and Cooperativity of Magnesium Chelatase from Synechocystis sp. PCC6803*
TLDR
It is demonstrated that, in vitro, this catalyzed reaction requires hydrolysis of ∼15 MgATP2– and that the chelation partial reaction is energetically unfavorable, under the authors' assay conditions, with a ΔG°′ of 25–33 kJ mol–1. Expand
Assay, purification, and characterization of cobaltochelatase, a unique complex enzyme catalyzing cobalt insertion in hydrogenobyrinic acid a,c-diamide during coenzyme B12 biosynthesis in Pseudomonas denitrificans
TLDR
This report provides the first evidence that hydrogenobyrinic acid and its a,c-diamide derivative are indeed precursors of adenosylcobalamin but also demonstrates that precorrin-6x, precorn-6y, and precorin-8x, three established precursor of hydrogenobyrsinic acid, are also on the pathway to cobalamin. Expand
The many faces of vitamin B12: catalysis by cobalamin-dependent enzymes.
TLDR
Understanding of the reaction mechanisms of B12 enzymes has been greatly enhanced by the availability of large amounts of enzyme that have afforded detailed structure-function studies, and these recent advances are the subject of this review. Expand
Magnesium-protoporphyrin chelatase of Rhodobacter sphaeroides: reconstitution of activity by combining the products of the bchH, -I, and -D genes expressed in Escherichia coli.
TLDR
The photosynthetic bacterium Rhodobacter sphaeroides has been used as a model system for the study of the Mg chelation reaction and the implications for chlorophyll biosynthesis in plants are discussed. Expand
Characterization of the Cobaltochelatase CbiXL
TLDR
Redox potentiometry coupled with optical spectroscopy allowed the midpoint potential of the redox center to be determined for the CbiXL from both B. megaterium and Synechocystis and confirmed the presence of an iron-sulfur center. Expand
...
1
2
3
...