scholarly journals Microbial and Genetic Resources for Cobalamin (Vitamin B12) Biosynthesis: From Ecosystems to Industrial Biotechnology

2021 ◽  
Vol 22 (9) ◽  
pp. 4522
Author(s):  
Larissa Balabanova ◽  
Liudmila Averianova ◽  
Maksim Marchenok ◽  
Oksana Son ◽  
Liudmila Tekutyeva
Keyword(s):  
Vitamin B12 ◽  
Genetic Resources ◽  
Positive Impact ◽  
Metagenomic Data ◽  
Metabolic Reconstruction ◽  
Industrial Biotechnology ◽  
Natural Ecosystems ◽  
Pseudomonas Denitrificans ◽  
Cobalamin Biosynthesis ◽  
Industrial Strains

Many microbial producers of coenzyme B12 family cofactors together with their metabolically interdependent pathways are comprehensively studied and successfully used both in natural ecosystems dominated by auxotrophs, including bacteria and mammals, and in the safe industrial production of vitamin B12. Metabolic reconstruction for genomic and metagenomic data and functional genomics continue to mine the microbial and genetic resources for biosynthesis of the vital vitamin B12. Availability of metabolic engineering techniques and usage of affordable and renewable sources allowed improving bioprocess of vitamins, providing a positive impact on both economics and environment. The commercial production of vitamin B12 is mainly achieved through the use of the two major industrial strains, Propionobacterium shermanii and Pseudomonas denitrificans, that involves about 30 enzymatic steps in the biosynthesis of cobalamin and completely replaces chemical synthesis. However, there are still unresolved issues in cobalamin biosynthesis that need to be elucidated for future bioprocess improvements. In the present work, we review the current state of development and challenges for cobalamin (vitamin B12) biosynthesis, describing the major and novel prospective strains, and the studies of environmental factors and genetic tools effecting on the fermentation process are reported.

scholarly journals Biosynthesis of vitamin B12 in Pseudomonas denitrificans: the biosynthetic sequence from precorrin-6y to precorrin-8x is catalyzed by the cobL gene product.

1992 ◽  
Vol 174 (3) ◽  
pp. 1050-1052 ◽  
Author(s):  
F Blanche ◽  
A Famechon ◽  
D Thibaut ◽  
L Debussche ◽  
B Cameron ◽  
...  
Keyword(s):  
Vitamin B12 ◽  
Gene Product ◽  
Pseudomonas Denitrificans

Aerobic synthesis of vitamin B12: ring contraction and cobalt chelation

2005 ◽  
Vol 33 (4) ◽  
pp. 815-819 ◽  
Author(s):  
D. Heldt ◽  
A.D. Lawrence ◽  
M. Lindenmeyer ◽  
E. Deery ◽  
P. Heathcote ◽  
...  
Keyword(s):  
Vitamin B12 ◽  
Metal Ion ◽  
Biosynthetic Pathway ◽  
Rhodobacter Capsulatus ◽  
Chlorophyll Synthesis ◽  
Subsequent Reduction ◽  
Ring Contraction ◽  
Contraction Process ◽  
Cobalamin Biosynthesis ◽  
Haem Iron

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 information is known about its mechanism. Recent work has established that in bacteria such as Rhodobacter capsulatus, CobG is substituted by an isofunctional protein called CobZ. This protein has been shown to contain flavin, haem and Fe-S centres. A mechanism is proposed to explain the function of CobZ. Another interesting aspect of the aerobic cobalamin biosynthetic pathway is cobalt insertion, which displays some similarity to the process of magnesium chelation in chlorophyll synthesis. The genetic requirements of cobalt chelation and the subsequent reduction of the metal ion are discussed.

scholarly journals Effect of mutations in the transmethylase and dehydrogenase/chelatase domains of sirohaem synthase (CysG) on sirohaem and cobalamin biosynthesis

1998 ◽  
Vol 330 (1) ◽  
pp. 121-129 ◽  
Author(s):  
C. Sarah WOODCOCK ◽  
Evelyne RAUX ◽  
Florence LEVILLAYER ◽  
Claude THERMES ◽  
Alain RAMBACH ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Catalytic Activity ◽  
Catalytic Domain ◽  
Conserved Residues ◽  
Pseudomonas Denitrificans ◽  
E Coli ◽  
Cobalamin Biosynthesis ◽  
N Terminus ◽  
Low Levels ◽  
Cobyric Acid

The Escherichia coli CysG protein (sirohaem synthase) catalyses four separate reactions that are required for the transformation of uroporphyrinogen III into sirohaem, initially two S-adenosyl-L-methionine-dependent transmethylations at positions 2 and 7, mediated through the C-terminal, or CysGA, catalytic domain of the protein, and subsequently a ferrochelation and dehydrogenation, mediated through the N-terminal, or CysGB, catalytic domain of the enzyme. This report describes how the deletion of the NAD+-binding site of CysG, located within the first 35 residues of the N-terminus, is detrimental to the activity of CysGB but does not affect the catalytic activity of CysGA, whereas the mutation of a number of phylogenetically conserved residues within CysGA is detrimental to the transmethylation reaction but does not affect the activity of CysGB. Further studies have shown that CysGB is not essential for cobalamin biosynthesis because the presence of the Salmonella typhimurium CobI operon with either cysGA or the Pseudomonas denitrificans cobA are sufficient for the synthesis of cobyric acid in an E. coli cysG deletion strain. Evidence is also presented to suggest that a gene within the S. typhimurium CobI operon might act as a chelatase that, at low levels of cobalt, is able to aid in the synthesis of sirohaem.

scholarly journals Biosynthesis of vitamin B12: the preparative multi-enzyme synthesis of precorrin-3A and 20-methylsirohydrochlorin (a 2,7,20-trimethylisobacteriochlorin)

1996 ◽  
Vol 313 (1) ◽  
pp. 335-342 ◽  
Author(s):  
N. J. Patrick STAMFORD ◽  
Joël CROUZET ◽  
Béatrice CAMERON ◽  
Alex I. D. ALANINE ◽  
Andrew R. PITT ◽  
...  
Keyword(s):  
Vitamin B12 ◽  
Large Scale ◽  
Enzyme Preparation ◽  
Enzyme System ◽  
Enzyme Synthesis ◽  
High Yield ◽  
Pseudomonas Denitrificans ◽  
E Coli ◽  
Plasmid Construct ◽  
Porphobilinogen Synthase

The Bacillus subtilis genes hemB, hemC and hemD, encoding respectively the enzymes porphobilinogen synthase, hydroxymethylbilane synthase and uroporphyrinogen III synthase, have been expressed in Escherichia coli using a single plasmid construct. An enzyme preparation from this source converts 5-aminolaevulinic acid (ALA) preparatively and in high yield into uroporphyrinogen III. The Pseudomonas denitrificans genes cobA and cobI, encoding respectively the enzymes S-adenosyl-L-methionine:uroporphyrinogen III methyltransferase (SUMT) and S-adenosyl-L-methionine:precorrin-2 methyltransferase (SP2MT), were also expressed in E. coli. When SUMT was combined with the coupled-enzyme system that produces uroporphyrinogen III, precorrin-2 was synthesized from ALA, and when SP2MT was also added the product from the coupling of five enzymes was precorrin-3A. Both of these products are precursors of vitamin B12, and they can be used directly for biosynthetic experiments or isolated as their didehydro octamethyl esters in > 40% overall yield. The enzyme system which produces precorrin-3A is sufficiently stable to allow long incubations on a large scale, affording substantial quantities (15-20 mg) of product.

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