Linked Life Data

8063787

Source:http://linkedlifedata.com/resource/pubmed/id/8063787

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
34
pubmed:dateCreated
1994-9-22
pubmed:abstractText
The subunit requirements for NADP+ reduction by photosystem I were assessed in mutants of Synechocystis sp. PCC 6803 created by targeted inactivation of the psaD, psaE, psaF, and psaL genes. The PsaE-less, PsaF-PsaJ-less, and PsaL-less mutants showed normal photoautotrophic growth, while the growth of PsaD-less mutants was slower without glucose. In isolated wild-type membranes, the rate of flavodoxin reduction and flavodoxin-mediated NADP+ reduction were 800 and 480 mumol/mg of chlorophyll/h, respectively. The rate of ferredoxin-mediated NADP+ photoreduction was 460 mumol/mg of chlorophyll/h. There was no diminution in NADP+ photoreduction in membranes isolated from the PsaF-less and PsaL-less mutants. The rates of ferredoxin-mediated NADP+ photoreduction in membranes of the PsaE-less mutants were 25 mumol/mg of chlorophyll/h. However, the rate of flavodoxin reduction was 380 mumol/mg of chlorophyll/h, and that of flavodoxin-mediated NADP+ photoreduction was 170 mumol/mg of chlorophyll/h. PsaD-less membranes showed < 20% of the wild-type rates of flavodoxin-mediated NADP+ photoreduction, but were completely deficient in ferredoxin-mediated NADP+ photoreduction. Therefore, the roles of PsaE and PsaD are more crucial for "docking" of ferredoxin than of flavodoxin. Proteolysis studies showed that while PsaD was susceptible to rapid in vitro degradation by thermolysin, the number and sizes of protease-resistant fragments were not affected by the absence of PsaE. Protease accessibility studies further indicated that the C-terminal domain of PsaD is surface-exposed on the n-side. These results suggest that PsaE and the C-terminal domain of PsaD generate the docking site for the electron acceptors of photosystem I.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
26
pubmed:volume
269
pubmed:geneSymbol
psaE, psaH, psaI, psaJ
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
21512-8
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1994
pubmed:articleTitle
Mutational analysis of photosystem I polypeptides in Synechocystis sp. PCC 6803. Subunit requirements for reduction of NADP+ mediated by ferredoxin and flavodoxin.
pubmed:affiliation
Division of Biology, Kansas State University, Manhattan 66506-4901.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, Non-P.H.S.