Bacteriochlorophyll

{{Chembox

| Name = Bacteriochlorophyll a

| ImageFile = BacterioChlorophyll a.svg

| ImageCaption =

| IUPACName = [methyl (3S,4S,13R,14R,21R)-9-acetyl-14-ethyl-4,8,13,18-tetramethyl-20-oxo-3-(3-oxo-3-([(2E,7R,11R)-3,7,11,15-tetramethylhexadec-2-en-1-yl]oxy)propyl)-13,14-dihydrophorbine-21-carboxylatato(2−)-kappa4N23,N24,N25,N26]magnesium

|Section1={{Chembox Identifiers

| CASNo = 17499-98-8

| CASNo_Ref = {{cascite|correct|CAS}}

| ChEBI = 30033

| PubChem = 11953947

| ChemSpiderID = 21169457

| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}

| KEGG = C11242

| SMILES = CC[C@@H]1[C@@H](C)C2=N/C/1=C\c3c(C)c4C(=O)[C@H](C(=O)OC)\C\5=C/6\N=C(\C=C\7/N([Mg]n3c45)\C(=C/2)\C(=C7C)C(=O)C)[C@@H](C)[C@@H]6CCC(=O)OC\C=C(/C)\CCC[C@H](C)CCC[C@H](C)CCCC(C)C

| InChI = 1S/C55H75N4O6.Mg/c1-13-39-34(7)41-29-46-48(38(11)60)36(9)43(57-46)27-42-35(8)40(52(58-42)50-51(55(63)64-12)54(62)49-37(10)44(59-53(49)50)28-45(39)56-41)23-24-47(61)65-26-25-33(6)22-16-21-32(5)20-15-19-31(4)18-14-17-30(2)3;/h25,27-32,34-35,39-40,51H,13-24,26H2,1-12H3,(H-,56,57,58,59,60,62);/q-1;+2/p-1/b33-25+;/t31-,32-,34-,35+,39-,40+,51-;/m1./s1

| InChI_Ref = {{stdinchicite|correct|EBI}}

| InChIKey = DSJXIQQMORJERS-AGGZHOMASA-M

}}

|Section2={{Chembox Properties

| Formula = {{chem2|MgC55H74N4O6}}

| Mg=1|C=55|H=74|N=4|O=6

| Appearance = Light green to blue-green powder

| Density =

| MeltingPt =

| BoilingPt =

| Solubility = }}

|Section3={{Chembox Hazards

| MainHazards =

| FlashPt =

| AutoignitionPt = }}

}}

Bacteriochlorophylls (BChl) are photosynthetic pigments that occur in various phototrophic bacteria. They were discovered by C. B. van Niel in 1932.{{cite journal |doi=10.1007/BF00454965 |title=On the morphology and physiology of the purple and green sulphur bacteria |year=1932 |last1=Niel |first1=C. B. |s2cid=19597530 |journal=Archiv für Mikrobiologie |volume=3 |pages=1–112 }}

They are related to chlorophylls, which are the primary pigments in plants, algae, and cyanobacteria. Organisms that contain bacteriochlorophyll conduct photosynthesis to sustain their energy requirements, but the process is anoxygenic and does not produce oxygen as a byproduct. They use wavelengths of light not absorbed by plants or cyanobacteria. Replacement of {{chem2|Mg(2+)}} with protons gives bacteriophaeophytin (BPh), the phaeophytin form.

class="wikitable"

|+ List of major bacteriochlorophylls

! Pigment

! Taxa

! in vivo infrared absorption maximum (nm)

BChl a

| Purple bacteria, Heliobacteria, Green Sulfur Bacteria, Chloroflexota, Chloracidobacterium thermophilum{{Citation| last1 = Bryant | first1 = Donald A.| title = Candidatus Chloracidobacterium thermophilum: An Aerobic Phototrophic Acidobacterium| journal = Science| volume = 317| issue = 5837| pages = 523–526| date = 2007-07-27| doi = 10.1126/science.1143236| pmid = 17656724| last2 = Costas| first2 = AM| last3 = Maresca| first3 = JA| last4 = Chew| first4 = AG| last5 = Klatt| first5 = CG| last6 = Bateson| first6 = MM| last7 = Tallon| first7 = LJ| last8 = Hostetler| first8 = J| last9 = Nelson| first9 = WC|name-list-style=vanc| display-authors = 1| bibcode = 2007Sci...317..523B| s2cid = 20419870}}

| 805, 830–890

BChl b

| Purple bacteria

| 835–850, 1020–1040

BChl c

| Green sulfur bacteria, Chloroflexota, C. thermophilum, C. tepidum

| 745–755

BChl d

| Green sulfur bacteria

| 705–740

BChl e

| Green sulfur bacteria

| 719–726

BChl f

| (Discovered by mutation of BChl e synthesis by analogy to BChl c/d. Not evolutionarily favorable.){{cite journal | last1 = Vogl | first1 = Kajetan| title = Bacteriochlorophyll f: properties of chlorosomes containing the "forbidden chlorophyll"| journal = Front. Microbiol.| volume = 3 | pages = article 298, pages 1–12 | date = 2012-08-10| doi = 10.3389/fmicb.2012.00298| pmid = 22908012| last2 = Tank| first2 = M| last3 = Orf| first3 = GS| last4 = Blankenship| first4 = RE| last5 = Bryant| first5 = DA|name-list-style=vanc| display-authors = 1 | pmc=3415949| doi-access = free}}

| 700–710

BChl g

| Heliobacteria

| 670, 788

BacterioChlorophyll a.svg|bacteriochlorophyll a

BacterioChlorophyll b.svg|bacteriochlorophyll b

BacterioChlorophyll c.svg|bacteriochlorophyll c

BacterioChlorophyll d.svg|bacteriochlorophyll d

BacterioChlorophyll e.svg|bacteriochlorophyll e

Bacteriochlorophyll f.svg|bacteriochlorophyll f

BacterioChlorophyll g.svg|bacteriochlorophyll g

Structure

File:Porphyrin, chlorin, bacteriochlorins.pngs comparing porphin, chlorin, bacteriochlorin, and isobacteriochlorin. Note relocation of C=C double bond between the two bacteriochlorin isomers. There are two π electrons (symbolized by π e⁻) for every double bond in the macrocycle.]]

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, e, and f are chlorins, meaning their molecules have a chlorin macrocycle ring with one reduced pyrrole ring (D).{{cite book |doi= 10.1007/0-306-47954-0_8 |chapter= Biosynthesis and Structures of the Bacteriochlorophylls |title= Anoxygenic Photosynthetic Bacteria |series= Advances in Photosynthesis and Respiration |year= 2004 |last1= Senge |first1= Mathias O. |last2= Smith |first2= Kevin M. |volume= 2 |pages= 137–151 |isbn= 0-7923-3681-X }}

Bacteriochlorophylls c to f occur in the form of closely related homologs with different alkyl groups attached to pyrrole rings B and C and are illustrated above in their simplest versions, esterified with the sesquiterpene alcohol farnesol.{{cite journal |doi=10.1002/cptc.201700164 |title=In Vivo Energy Transfer from Bacteriochlorophyll c , d , e , or f to Bacteriochlorophyll a in Wild-Type and Mutant Cells of the Green Sulfur Bacterium Chlorobaculum limnaeum |year=2018 |last1=Harada |first1=Jiro |last2=Shibata |first2=Yutaka |last3=Teramura |first3=Misato |last4=Mizoguchi |first4=Tadashi |last5=Kinoshita |first5=Yusuke |last6=Yamamoto |first6=Ken |last7=Tamiaki |first7=Hitoshi |journal=ChemPhotoChem |volume=2 |issue=3 |pages=190–195 }} Most of the variation occurs in the 8 and 12 positions and can be attributed to methyltransferase variation.{{cite journal |last1=Gomez Maqueo Chew |first1=A |last2=Frigaard |first2=NU |last3=Bryant |first3=DA |title=Bacteriochlorophyllide c C-8(2) and C-12(1) methyltransferases are essential for adaptation to low light in Chlorobaculum tepidum. |journal=Journal of Bacteriology |date=September 2007 |volume=189 |issue=17 |pages=6176–84 |doi=10.1128/JB.00519-07 |pmid=17586634|pmc=1951906 }} BChl c_S is a term for 8-ethyl,12-methyl homolog of BChl c.{{cite journal |last1=Gloe |first1=A |last2=Risch |first2=N |title=Bacteriochlorophyll cs, a new bacteriochlorophyll from Chloroflexus aurantiacus. |journal=Archives of Microbiology |date=1 August 1978 |volume=118 |issue=2 |pages=153–6 |doi=10.1007/BF00415723 |pmid=697505|s2cid=20011765 }}

Bacteriochlorophyll g has a vinyl group in ring (A), at position 8.{{cite journal |doi=10.1016/j.bbabio.2013.06.007 |title=Completion of biosynthetic pathways for bacteriochlorophyll g in Heliobacterium modesticaldum: The C8-ethylidene group formation |year=2013 |last1=Tsukatani |first1=Yusuke |last2=Yamamoto |first2=Haruki |last3=Mizoguchi |first3=Tadashi |last4=Fujita |first4=Yuichi |last5=Tamiaki |first5=Hitoshi |journal=Biochimica et Biophysica Acta (BBA) - Bioenergetics |volume=1827 |issue=10 |pages=1200–1204 |pmid=23820336 |doi-access=free }}

Biosynthesis

File:Chlorophyllide a.svg

There are a large number of known bacteriochlorophylls{{cite journal |doi=10.1146/annurev.micro.61.080706.093242 |title=Chlorophyll Biosynthesis in Bacteria: The Origins of Structural and Functional Diversity |year=2007 |last1=Chew |first1=Aline Gomez Maqueo |last2=Bryant |first2=Donald A. |journal=Annual Review of Microbiology |volume=61 |pages=113–129 |pmid=17506685 }} but all have features in common since the biosynthetic pathway involves chlorophyllide a (Chlide a) as an intermediate.{{cite journal |title=Biosynthesis of chlorophylls from protoporphyrin IX |last =Willows | first =Robert D. | journal =Natural Product Reports | year =2003 | volume = 20 |issue = 6 | pages =327–341 |doi=10.1039/B110549N |pmid=12828371}}

Chlorin-cored BChls (c to f) are produced by a series of enzymatic modifications on the sidechain of Chlide a, much like how Chl b, d, e are made. The bacteriochlorin-cored BChls a, b, g require a unique step to reduce the double bond between C7 and C8, which is performed by chlorophyllide a reductase (COR).

Isobacteriochlorins, in contrast, are biosynthesised from uroporphyrinogen III in a separate pathway that leads, for example, to siroheme, cofactor F₄₃₀ and cobalamin. The common intermediate is sirohydrochlorin.{{cite journal |doi=10.1039/B002635M |title=Tetrapyrroles: The pigments of life: A Millennium review |year=2000 |last1=Battersby |first1=Alan R. |journal=Natural Product Reports |volume=17 |issue=6 |pages=507–526 |pmid=11152419 }}

References

Category:Photosynthetic pigments

Category:Tetrapyrroles

de:Chlorophylle#Chemische Struktur bei anoxygenen Phototrophen: Bakteriochlorophylle (Bchl)