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The 17-propionate esterifying variants of bacteriochlorophyll-a and bacteriopheophytin-a in purple photosynthetic bacteria

Paper ID Volume ID Publish Year Pages File Format Full-Text
29804 44440 2015 6 PDF Available
Title
The 17-propionate esterifying variants of bacteriochlorophyll-a and bacteriopheophytin-a in purple photosynthetic bacteria
Abstract

•Bacteriochlorophyll-a and bacteriopheophytin-a in purple bacteria were investigated.•Esterifying groups in 17-propionate residues of such chlorophylls were analyzed.•All bacteria contained geranylgeranyl(GG), dihydro-GG and tetrahydro-GG as esters.•The production of bacteriopheophytin-a esterified with GG was relatively suppressed.

Most purple photosynthetic bacteria contain bacteriochlorophyll(BChl)-a (a magnesium complex) and bacteriopheophytin(BPhe)-a (its free base) as their photoactive pigments. These pigments are composed of two parts: a cyclic tetrapyrrole as the chromophore and a long hydrocarbon-chain as the propionate-type esterifying group at the 17-position. The hydrocarbon-chain is usually an isoprenoid-type C20 phytyl (Phy) group in both the pigments. In the ester group of BChl-a, several variants such as geranylgeranyl (GG), dihydrogeranylgeranyl (DHGG) and tetrahydrogeranylgeranyl (THGG) groups were found in the final stage of BChl-a biosynthesis. On the other hand, the esterifying variants in BPhe-a have not been studied as much due to the lower levels of this pigment relative to BChl-a. The esterifying group does not affect the electronic absorption properties of such pigments in the monomeric state, but drastically alters the hydrophobicity. In this study, BChl-a and BPhe-a in the six phylogenetically distinct classes of purple bacteria were analyzed in terms of their esterifying groups in the 17-propionate residues, using high-performance liquid chromatography. Both BChls-a and BPhes-a carrying GG, DHGG and THGG in addition to the usual Phy were found for all the bacterial species studied at measurable levels. In some of the species, the ratio of BPhes-a esterified with GG, DHGG and THGG over the total BPhe-a drastically decreased in comparison with that of the corresponding BChls-a. Especially, the relative content of BPhe-a with GG largely decreased. This observation might indicate that BPhe-a as a cofactor of reaction centers was preferentially esterified with partially reduced and flexible chains (THGG and Phy) rather than less reduced and rigid ones (GG and DHGG).

Keywords
Bacteriochlorophyll-a; Bacteriopheophytin-a; Propionate-type ester group; Purple bacteria; Geranylgeranyl reductase; High-performance liquid chromatography
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The 17-propionate esterifying variants of bacteriochlorophyll-a and bacteriopheophytin-a in purple photosynthetic bacteria
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Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Photochemistry and Photobiology B: Biology - Volume 142, January 2015, Pages 244–249
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us