Abstract
delta-Aminolevulinic acid and trimethylisobacteriochlorin are converted by cell-free protein preparations from Pseudomonas denitrificans into a metal-free pigment, precorrin-6x. This pigment, which accumulates when the cell-free system lacks NADPH, can be enzymically converted in high yield (greater than 50%) into hydrogenobyrinic acid by the complete enzyme preparation. Double-labeling experiments establish that precorrin-6x carries five C-methyl groups, which appear at C-1, C-2, C-7, C-12 alpha, and C-17 of the hydrogenobyrinic acid formed enzymically from precorrin-6x. This precursor of the corrin macrocycle is at the dehydrocorrin level of oxidation, has undergone ring contraction and extrusion of C-20, but still carries the acetic acid side chain at C-12. It is demonstrated that the conversion of precorrin-6x into hydrogenobyrinic acid specifically requires an NADPH-dependent reduction step.
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Selected References
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- Battersby A. R., Bushell M. J., Jones C., Lewis N. G., Pfenninger A. Biosynthesis of vitamin B12: identity of fragment extruded during ring contraction to the corrin macrocycle. Proc Natl Acad Sci U S A. 1981 Jan;78(1):13–15. doi: 10.1073/pnas.78.1.13. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Crouzet J., Cameron B., Cauchois L., Rigault S., Rouyez M. C., Blanche F., Thibaut D., Debussche L. Genetic and sequence analysis of an 8.7-kilobase Pseudomonas denitrificans fragment carrying eight genes involved in transformation of precorrin-2 to cobyrinic acid. J Bacteriol. 1990 Oct;172(10):5980–5990. doi: 10.1128/jb.172.10.5980-5990.1990. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Dresow B., Schlingmann G., Ernst L., Koppenhagen V. B. Extracellular metal-free corrinoids from Rhodopseudomonas spheroides. J Biol Chem. 1980 Aug 25;255(16):7637–7644. [PubMed] [Google Scholar]
- Leeper F. J. The biosynthesis of porphyrins, chlorophylls, and vitamin B12. Nat Prod Rep. 1989 Apr;6(2):171–203. doi: 10.1039/np9890600171. [DOI] [PubMed] [Google Scholar]
- Mombelli L., Nussbaumer C., Weber H., Müller G., Arigoni D. Biosynthesis of vitamin B12: nature of the volatile fragment generated during formation of the corrin ring system. Proc Natl Acad Sci U S A. 1981 Jan;78(1):11–12. doi: 10.1073/pnas.78.1.11. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Scott A. I., Kajiwara M., Santander P. J. Biosynthesis of vitamin B12: concerning the origin of the methine protons of the corrin nucleus. Proc Natl Acad Sci U S A. 1987 Oct;84(19):6616–6618. doi: 10.1073/pnas.84.19.6616. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Thibaut D., Blanche F., Debussche L., Leeper F. J., Battersby A. R. Biosynthesis of vitamin B12: structure of precorrin-6x octamethyl ester. Proc Natl Acad Sci U S A. 1990 Nov;87(22):8800–8804. doi: 10.1073/pnas.87.22.8800. [DOI] [PMC free article] [PubMed] [Google Scholar]