Bacteriopheophytin g: properties and some speculations on a possible primary role for bacteriochlorophylls b and g in the biosynthesis of chlorophylls

Journal Article · Fri May 01 00:00:00 EDT 1987 · Proc. Natl. Acad. Sci. U.S.A.; (United States)

DOI:https://doi.org/10.1073/pnas.84.9.2570· OSTI ID:5987102

Michalski, T J; Hunt, J E; Bowman, M K; Smith, U; Bardeen, K; Gest, H; Norris, J R; Katz, J J

Bacteriopheophytin g and small amounts of bacteriochlorophyll g have been obtained in high purity from the recently discovered photosynthetic bacterium Heliobacterium chlorum. Preparative methods and precautions in handling these sensitive compounds are described. The compounds have been characterized by californium-252 plasma desorption mass spectrometry, HPLC, visible absorption, and electron spin resonance spectroscopy. The results agree with the structure of bacteriochlorophyll g advanced by H. Brockmann and A. Lipinski, with the exception that the present authors find the esterifying alcohol to be farnesol and not geranylgeraniol as originally suggested. Zero field splitting parameters of triplet state bacteriopheophytin g and the ESR properties of the cation free radical of bacteriochlorophyll g are reported. The photoisomerization of the subject compounds has been studied. Bacteriopheophytin g undergoes photoisomerization in white light to pheophytin a with a half-time of approx.42 min. They suggest that all of the chlorophylls are biosynthesized from a common intermediate containing an ethylidine group, double bond CH single bond CH/sub 3/, such as it present in bacteriochlorophylls b and g.

• Research Organization: Argonne National Lab., IL
• OSTI ID: 5987102
• Journal Information: Proc. Natl. Acad. Sci. U.S.A.; (United States), Vol. 84:9
• Country of Publication: United States
• Language: English

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