Linked Life Data

20087600

Source:http://linkedlifedata.com/resource/pubmed/id/20087600

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
2010-2-12
pubmed:abstractText
In plants, chlorophyll is actively synthesized from glutamate in the developmental phase and is degraded into non-fluorescent chlorophyll catabolites during senescence. The chlorophyll metabolism must be strictly regulated because chlorophylls and their intermediate molecules generate reactive oxygen species. Many mechanisms have been proposed for the regulation of chlorophyll synthesis including gene expression, protein stability, and feedback inhibition. However, information on the regulation of chlorophyll degradation is limited. The conversion of chlorophyll b to chlorophyll a is the first step of chlorophyll degradation. In order to understand the regulatory mechanism of this reaction, we isolated a mutant which accumulates 7-hydroxymethyl chlorophyll a (HMChl), an intermediate molecule of chlorophyll b to chlorophyll a conversion, and designated the mutant hmc1. In addition to HMChl, hmc1 accumulated pheophorbide a, a chlorophyll degradation product, when chlorophyll degradation was induced by dark incubation. These results indicate that the activities of HMChl reductase (HAR) and pheophorbide a oxygenase (PaO) are simultaneously down-regulated in this mutant. We identified a mutation in the AtNAP1 gene, which encodes a subunit of the complex for iron-sulfur cluster formation. HAR and PaO use ferredoxin as a reducing power and PaO has an iron-sulfur center; however, there were no distinct differences in the protein levels of ferredoxin and PaO between wild type and hmc1. The concerted regulation of chlorophyll degradation is discussed in relation to the function of AtNAP1.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
1432-2048
pubmed:author
pubmed:issnType
Electronic
pubmed:volume
231
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
939-49
pubmed:meshHeading
pubmed:year
2010
pubmed:articleTitle
Involvement of AtNAP1 in the regulation of chlorophyll degradation in Arabidopsis thaliana.
pubmed:affiliation
Institute of Low Temperature Science, Hokkaido University, N19W8, Kita-ku, Sapporo 060-0819, Japan.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't