Bacteriochlorophyll
Oxford Dictionary of Biochemistry:
Top
bacteriochlorophyll
any of the chlorophylls of photosynthetic bacteria. They differ structurally from the chlorophylls of higher plants. Bacteriochlorophylls a to g are known. Bacteriochlorophylls a and b are the best known, being the photosynthetic pigments of purple bacteria. Their purple colour results from the fact that they are reduced in both rings B and D, and thus may be regarded as tetrahydropyrroles. Tetrapyrrole carbon atoms and carbon rings are numbered according to the Fischer and IUPAC systems as indicated below. The structure of bacteriochlorophyll a is shown. Bacteriochlorophyll b has =CH — CH3 in place of the ethyl group on ring B of bacteriochlorophyll a. In some bacteriochlorophylls a the phytyl group may be replaced by a geranylgeranyl group. Bacteriochlorophylls c, d, and e are antenna pigments of Chlorobiaceae, located in chlorobium vesicles (a core structure is shown). These are dihydropyrrole structures, being reduced in ring D only. The esterifying alcohol is farnesol. In these bacteriochlorophylls, the side chain R1 (see core structure) on ring B varies, being ethyl, n-propyl, or isobutyl (in bacteriochlorophyll d neopentyl is also possible). On ring C the side chain R2 is ethyl (in bacteriochlorophyll d methyl is also possible). R3 is methyl in bacteriochlorophylls c and e, and H in bacteriochlorophyll d.
| bactericidin, bactericide, bacterial conjugation | |
| bacteriocin, bacteriocinogenic factor, bacterioferritin |
Wikipedia on Answers.com:
Top
Bacteriochlorophyll
Bacteriochlorophylls are photosynthetic pigments that occur in various phototrophic bacteria. They were discovered by Von Neil in 1932 . They are related to chlorophylls, which are the primary pigments in plants, algae, and cyanobacteria. Groups that contain bacteriochlorophyll conduct photosynthesis, but do not produce oxygen. They use wavelengths of light not absorbed by plants or Cyanobacteria. Different groups contain different types of bacteriochlorophyll:
| Pigment | Bacterial group | in vivo infrared absorption maximum (nm) |
|---|---|---|
| Bacteriochlorophyll a | Purple bacteria (= Proteobacteria), Chloracidobacterium thermophilum[1] | 805, 830-890 |
| Bacteriochlorophyll b | Purple bacteria | 835-850, 1020-1040 |
| Bacteriochlorophyll c | Green sulfur bacteria, Chloroflexi, C. thermophilum | 745-755 |
| Bacteriochlorophyll cs | Chloroflexi | 740 |
| Bacteriochlorophyll d | Green sulfur bacteria | 705-740 |
| Bacteriochlorophyll e | Green sulfur bacteria | 719-726 |
| Bacteriochlorophyll g | Heliobacteria | 670, 788 |
Bacteriochlorophylls a, b, and g are bacteriochlorins, meaning their molecules have a bacteriochlorin macrocycle ring with two reduced pyrrole rings (B and D). Bacteriochlorophylls c, d and e are chlorins, meaning their molecules have a chlorin macrocycle ring with one reduced pyrrole ring (D).
References
- ^ Bryant, Donald A. et al. (2007-07-27), "Candidatus Chloracidobacterium thermophilum: An Aerobic Phototrophic Acidobacterium", Science 317 (5837): 523–526, doi:10.1126/science.1143236, PMID 17656724, http://www.sciencemag.org/cgi/content/abstract/317/5837/523
|
||||||||||||||||||||||||||||||||||||||||||||||||
|
|||||||||||||||||||||||||||||||||||||||||||||||
This entry is from Wikipedia, the leading user-contributed encyclopedia. It may not have been reviewed by professional editors (see full disclaimer)
Post a question - any question - to the WikiAnswers community:
Copyrights:
Oxford Dictionary of Biochemistry
Oxford University Press. Oxford Dictionary of Biochemistry and Molecular Biology © 1997, 2000, 2006 All rights reserved.
Read more
Mentioned in
Amoebobacter
(microbiology)
Lamprocystis
(microbiology)
purple bacteria
(microbiology)
Rhodospirillineae
(microbiology)
Chlorobium
(microbiology)
» More