The enigma of cobalamin (Vitamin B12) biosynthesis in Porphyromonas gingivalis. Identification and characterization of a functional corrin pathway

Roper, Jennifer M. and Raux-Deery, Evelyne and Brindley, Amanda A. and Schubert, Heidi L. and Gharbia, Saheer E. and Shah, Haroun N. and Warren, Martin J. (2000) The enigma of cobalamin (Vitamin B12) biosynthesis in Porphyromonas gingivalis. Identification and characterization of a functional corrin pathway. Journal of Biological Chemistry, 275 (51). pp. 40316-23. ISSN 0021-9258. (The full text of this publication is not currently available from this repository. You may be able to access a copy if URLs are provided)

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The ability of Porphyromonas gingivalis to biosynthesize tetrapyrroles de novo has been investigated. Extracts of the bacterium do not possess activity for 5- aminolevulinic-acid dehydratase or porphobilinogen deaminase, two key enzymes involved in the synthesis of uroporphyrinogen III. Similarly, it was not possible to detect any genetic evidence for these early enzymes with the use of degenerate polymerase chain reaction. However, the bacterium does appear to harbor some of the enzymes for cobalamin biosynthesis since cobyric acid, a pathway intermediate, was converted into cobinamide. Furthermore, degenerate polymerase chain reaction with primers to cbiP, which encodes cobyric-acid synthase, produced a fragment with a high degree of identity to Salmonella typhimurium cbiP. Indeed, the recently released genome sequence data confirmed the presence of cbiP together with 14 other genes of the cobalamin pathway. A number of these genes were cloned and functionally characterized. Although P. gingivalis harbors all the genes necessary to convert precorrin-2 into cobalamin, it is missing the genes for the synthesis of precorrin-2. Either the organism has a novel pathway for the synthesis of precorrin-2, or more likely, it has lost this early part of the pathway. The remainder of the pathway may be being maintained to act as a salvage route for corrin synthesis.

Item Type: Article
Uncontrolled keywords: Base Sequence Cloning, Molecular Corrinoids DNA Primers Genes, Bacterial Genetic Complementation Test Methylmalonyl-CoA Mutase/genetics Polymerase Chain Reaction Porphyrins/*metabolism Porphyromonas gingivalis/enzymology/growth & development/*metabolism Vitamin B 12/*biosynthesis
Subjects: Q Science
Divisions: Faculties > Science Technology and Medical Studies > School of Biosciences
Depositing User: Martin Warren
Date Deposited: 12 Oct 2009 08:28
Last Modified: 17 Jul 2014 13:30
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