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Xantha-l encodes a membrane subunit of the aerobic Mg-protoporphyrin IX monomethyl ester cyclase involved in chlorophyll biosynthesis

Rzeznicka, Kamila LU ; Walker, C J; Westergren, Tomas LU ; Kannangara, C G; von Wettstein, D; Merchant, S; Gough, Simon LU and Hansson, Mats LU (2005) In Proceedings of the National Academy of Sciences 102(16). p.5886-5891
Abstract
Chlorophyll biosynthesis is a process involving approximate to 20 different enzymatic steps. Half of these steps are common to the biosynthesis of other tetrapyrroles, such as heme. one of the least understood enzymatic steps is formation of the isocyclic ring, which is a characteristic feature of all (bacterio)chlorophyll molecules. In chloroplasts, formation of the isocyclic ring is an aerobic reaction catalyzed by Mg-protoporphyrin IX monomethyl ester cyclase. An in vitro assay for the aerobic cyclase reaction required membrane-bound and soluble components from the chloroplasts. Extracts from barley (Hordeum vulgare Q mutants at the Xantha-1 and Viridis-k loci showed no cyclase activity. Fractionation of isolated plastids by Percoll... (More)
Chlorophyll biosynthesis is a process involving approximate to 20 different enzymatic steps. Half of these steps are common to the biosynthesis of other tetrapyrroles, such as heme. one of the least understood enzymatic steps is formation of the isocyclic ring, which is a characteristic feature of all (bacterio)chlorophyll molecules. In chloroplasts, formation of the isocyclic ring is an aerobic reaction catalyzed by Mg-protoporphyrin IX monomethyl ester cyclase. An in vitro assay for the aerobic cyclase reaction required membrane-bound and soluble components from the chloroplasts. Extracts from barley (Hordeum vulgare Q mutants at the Xantha-1 and Viridis-k loci showed no cyclase activity. Fractionation of isolated plastids by Percoll gradient centrifugation showed that xantha-1 and viridis-k mutants are defective in components associated with chloroplast membranes. The Xantha-1 gene, corresponding to Arabidopsis thaliana CHL27, Rubrivivax gelatinosus acsF, Chlamydomonas reinhardtii CRD1, and CTH1 and situated at the short arm of barley chromosome 3 (3H), was cloned, and the mutations in xantha-l(35), xantha-l(81), and xantha-l(82) were characterized. This finding connected biochemical and genetic data because it demonstrated that Xantha-1 encodes a membrane-bound cyclase subunit. The evidence suggests that the aerobic cyclase requires at least one soluble and two membrane-bound components. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Proceedings of the National Academy of Sciences
volume
102
issue
16
pages
5886 - 5891
publisher
National Acad Sciences
external identifiers
  • pmid:15824317
  • wos:000228565200046
  • scopus:17644371000
ISSN
1091-6490
DOI
10.1073/pnas.0501784102
language
English
LU publication?
yes
id
8367cd64-dc9f-468d-9e0e-3939c74dea47 (old id 151464)
date added to LUP
2007-07-06 14:49:56
date last changed
2017-10-01 03:49:12
@article{8367cd64-dc9f-468d-9e0e-3939c74dea47,
  abstract     = {Chlorophyll biosynthesis is a process involving approximate to 20 different enzymatic steps. Half of these steps are common to the biosynthesis of other tetrapyrroles, such as heme. one of the least understood enzymatic steps is formation of the isocyclic ring, which is a characteristic feature of all (bacterio)chlorophyll molecules. In chloroplasts, formation of the isocyclic ring is an aerobic reaction catalyzed by Mg-protoporphyrin IX monomethyl ester cyclase. An in vitro assay for the aerobic cyclase reaction required membrane-bound and soluble components from the chloroplasts. Extracts from barley (Hordeum vulgare Q mutants at the Xantha-1 and Viridis-k loci showed no cyclase activity. Fractionation of isolated plastids by Percoll gradient centrifugation showed that xantha-1 and viridis-k mutants are defective in components associated with chloroplast membranes. The Xantha-1 gene, corresponding to Arabidopsis thaliana CHL27, Rubrivivax gelatinosus acsF, Chlamydomonas reinhardtii CRD1, and CTH1 and situated at the short arm of barley chromosome 3 (3H), was cloned, and the mutations in xantha-l(35), xantha-l(81), and xantha-l(82) were characterized. This finding connected biochemical and genetic data because it demonstrated that Xantha-1 encodes a membrane-bound cyclase subunit. The evidence suggests that the aerobic cyclase requires at least one soluble and two membrane-bound components.},
  author       = {Rzeznicka, Kamila and Walker, C J and Westergren, Tomas and Kannangara, C G and von Wettstein, D and Merchant, S and Gough, Simon and Hansson, Mats},
  issn         = {1091-6490},
  language     = {eng},
  number       = {16},
  pages        = {5886--5891},
  publisher    = {National Acad Sciences},
  series       = {Proceedings of the National Academy of Sciences},
  title        = {Xantha-l encodes a membrane subunit of the aerobic Mg-protoporphyrin IX monomethyl ester cyclase involved in chlorophyll biosynthesis},
  url          = {http://dx.doi.org/10.1073/pnas.0501784102},
  volume       = {102},
  year         = {2005},
}