An uncultivated crenarchaeota contains functional bacteriochlorophyll a synthase.
A fosmid clone 37F10 containing an archaeal 16S rRNA gene was screened out from a metagenomic library of Pearl River sediment, southern China. Sequence analysis of the 35 kb inserted fragment of 37F10 found that it contains a single 16S rRNA gene belonging to Miscellaneous Crenarchaeotal Group (MCG) and 36 open reading frames (ORFs). One ORF (orf11) encodes putative bacteriochlorophyll a synthase (bchG) gene. Bacteriochlorophyll a synthase gene has never been reported in a member of the domain Archaea, in accordance with the fact that no (bacterio)-chlorophyll has ever been detected in any cultivated archaea. The putative archaeal bchG (named as ar-bchG) was cloned and heterologously expressed in Escherichia coli. The protein was found to be capable of synthesizing bacteriochlorophyll a by esterification of bacteriochlorophyllide a with phytyl diphosphate or geranylgeranyl diphosphate. Furthermore, phylogenetic analysis clearly indicates that the ar-bchG diverges before the bacterial bchGs. Our results for the first time demonstrate that a key and functional enzyme for bacteriochlorophyll a biosynthesis does exist in Archaea.
Meng
Jun
J
School of Life Sciences, Xiamen University, Xiamen, Fujian, PR China.
Wang
Fengping
F
Wang
Feng
F
Zheng
Yanping
Y
Peng
Xiaotong
X
Zhou
Huaiyang
H
Xiao
Xiang
X
D019729:Carbon-Oxygen Ligases / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism*; D002681:China; D002735:Chlorophyllides / Q000378:metabolism; D003001:Cloning, Molecular; D016000:Cluster Analysis; D019615:Crenarchaeota / Q000201:enzymology* / Q000235:genetics; D019641:DNA, Archaeal / Q000737:chemistry / Q000235:genetics; D011756:Diphosphates / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics; D015870:Gene Expression; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D010802:Phylogeny; D011106:Polyisoprenyl Phosphates / Q000378:metabolism; D045483:Rivers / Q000382:microbiology*; D017422:Sequence Analysis, DNA; D017385:Sequence Homology
D002735:Chlorophyllides; D019641:DNA, Archaeal; D011756:Diphosphates; D011106:Polyisoprenyl Phosphates; C529546:phytyl diphosphate; C034388:chlorophyllide a; D019729:Carbon-Oxygen Ligases; C105512:bacteriochlorophyll a synthase; C002963:geranylgeranyl pyrophosphate