title: Identification of the chlE gene encoding oxygen-independent Mg-protoporphyrin IX monomethyl ester cyclase in cyanobacteria.
abstract: The fifth ring (E-ring) of chlorophyll (Chl) a is produced by Mg-protoporphyrin IX monomethyl ester (MPE) cyclase. There are two evolutionarily unrelated MPE cyclases: oxygen-independent (BchE) and oxygen-dependent (ChlA/AcsF) MPE cyclases. Although ChlA is the sole MPE cyclase in Synechocystis PCC 6803, it is yet unclear whether BchE exists in cyanobacteria. A BLAST search suggests that only few cyanobacteria possess bchE. Here, we report that two bchE candidate genes from Cyanothece strains PCC 7425 and PCC 7822 restore the photosynthetic growth and bacteriochlorophyll production in a bchE-lacking mutant of Rhodobacter capsulatus. We termed these cyanobacterial bchE orthologs "chlE."
authors.affiliation: Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan.
authors.forename: Kaori
authors.initials: K
authors.lastname: Yamanashi
authors.affiliation: Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan.
authors.forename: Kei
authors.initials: K
authors.lastname: Minamizaki
authors.affiliation: Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan. Electronic address: fujita@agr.nagoya-u.ac.jp.
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Fujita
mesh_terms: D000458:Cyanobacteria / Q000201:enzymology / Q000235:genetics*; D005798:Genes, Bacterial; D005816:Genetic Complementation Test; D010100:Oxygen / Q000378:metabolism*; D010802:Phylogeny; D010860:Pigments, Biological / Q000378:metabolism; D011524:Protoporphyrins / Q000145:classification / Q000235:genetics* / Q000378:metabolism
chemical_list: D010860:Pigments, Biological; D011524:Protoporphyrins; C033434:protoporphyrin IX monomethyl ester; D010100:Oxygen
keywords: AcsF; BchE; ChlA; Chlorophyll biosynthesis; Cyanobacteria; Mg-protoporphyrin IX monomethyl ester cyclase