Advanced

Recessiveness and Dominance in Barley Mutants Deficient in Mg-Chelatase Subunit D, an AAA Protein Involved in Chlorophyll Biosynthesis.

Axelsson, Eva LU ; Lundqvist, Joakim LU ; Sawicki, Artur ; Nilsson, Sara LU ; Schröder, Ingrid LU ; Al-Karadaghi, Salam LU ; Willows, Robert D and Hansson, Mats LU (2006) In Plant Cell 18(12). p.3606-3616
Abstract
Mg-chelatase catalyzes the insertion of Mg2+ into protoporphyrin IX at the first committed step of the chlorophyll biosynthetic pathway. It consists of three subunits: I, D, and H. The I subunit belongs to the AAA protein superfamily ( ATPases associated with various cellular activities) that is known to form hexameric ring structures in an ATP-dependant fashion. Dominant mutations in the I subunit revealed that it functions in a cooperative manner. We demonstrated that the D subunit forms ATP-independent oligomeric structures and should also be classified as an AAA protein. Furthermore, we addressed the question of cooperativity of the D subunit with barley (Hordeum vulgare) mutant analyses. The recessive behavior in vivo was explained by... (More)
Mg-chelatase catalyzes the insertion of Mg2+ into protoporphyrin IX at the first committed step of the chlorophyll biosynthetic pathway. It consists of three subunits: I, D, and H. The I subunit belongs to the AAA protein superfamily ( ATPases associated with various cellular activities) that is known to form hexameric ring structures in an ATP-dependant fashion. Dominant mutations in the I subunit revealed that it functions in a cooperative manner. We demonstrated that the D subunit forms ATP-independent oligomeric structures and should also be classified as an AAA protein. Furthermore, we addressed the question of cooperativity of the D subunit with barley (Hordeum vulgare) mutant analyses. The recessive behavior in vivo was explained by the absence of mutant proteins in the barley cell. Analogous mutations in Rhodobacter capsulatus and the resulting D proteins were studied in vitro. Mixtures of wild-type and mutant R. capsulatus D subunits showed a lower activity compared with wild-type subunits alone. Thus, the mutant D subunits displayed dominant behavior in vitro, revealing cooperativity between the D subunits in the oligomeric state. We propose a model where the D oligomer forms a platform for the stepwise assembly of the I subunits. The cooperative behavior suggests that the D oligomer takes an active part in the conformational dynamics between the subunits of the enzyme. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Plant Cell
volume
18
issue
12
pages
3606 - 3616
publisher
American Society of Plant Biologists
external identifiers
  • wos:000244177000020
  • scopus:33947505937
ISSN
1040-4651
DOI
10.1105/tpc.106.042374
language
English
LU publication?
yes
id
9d7676fb-2a39-43ca-8212-24677cc8ab81 (old id 164092)
alternative location
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=17158606&dopt=Abstract
date added to LUP
2016-04-01 15:58:28
date last changed
2020-02-12 07:22:30
@article{9d7676fb-2a39-43ca-8212-24677cc8ab81,
  abstract     = {Mg-chelatase catalyzes the insertion of Mg2+ into protoporphyrin IX at the first committed step of the chlorophyll biosynthetic pathway. It consists of three subunits: I, D, and H. The I subunit belongs to the AAA protein superfamily ( ATPases associated with various cellular activities) that is known to form hexameric ring structures in an ATP-dependant fashion. Dominant mutations in the I subunit revealed that it functions in a cooperative manner. We demonstrated that the D subunit forms ATP-independent oligomeric structures and should also be classified as an AAA protein. Furthermore, we addressed the question of cooperativity of the D subunit with barley (Hordeum vulgare) mutant analyses. The recessive behavior in vivo was explained by the absence of mutant proteins in the barley cell. Analogous mutations in Rhodobacter capsulatus and the resulting D proteins were studied in vitro. Mixtures of wild-type and mutant R. capsulatus D subunits showed a lower activity compared with wild-type subunits alone. Thus, the mutant D subunits displayed dominant behavior in vitro, revealing cooperativity between the D subunits in the oligomeric state. We propose a model where the D oligomer forms a platform for the stepwise assembly of the I subunits. The cooperative behavior suggests that the D oligomer takes an active part in the conformational dynamics between the subunits of the enzyme.},
  author       = {Axelsson, Eva and Lundqvist, Joakim and Sawicki, Artur and Nilsson, Sara and Schröder, Ingrid and Al-Karadaghi, Salam and Willows, Robert D and Hansson, Mats},
  issn         = {1040-4651},
  language     = {eng},
  number       = {12},
  pages        = {3606--3616},
  publisher    = {American Society of Plant Biologists},
  series       = {Plant Cell},
  title        = {Recessiveness and Dominance in Barley Mutants Deficient in Mg-Chelatase Subunit D, an AAA Protein Involved in Chlorophyll Biosynthesis.},
  url          = {http://dx.doi.org/10.1105/tpc.106.042374},
  doi          = {10.1105/tpc.106.042374},
  volume       = {18},
  year         = {2006},
}