Linked Life Data

15509839

Source:http://linkedlifedata.com/resource/pubmed/id/15509839

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
9
pubmed:dateCreated
2004-10-28
pubmed:abstractText
Oxygen-evolving photosystem II (PSII) complexes of Euglena gracilis were isolated and characterized. (1) The PSII complexes contained three extrinsic proteins of 33 kDa (PsbO), 23 kDa (PsbP) and 17 kDa (PsbQ), and showed oxygen-evolving activity of around 700 micromol O2 (mg Chl)(-1) h(-1) even in the absence of Cl- and Ca2+ ions. (2) NaCl-treatment removed not only PsbP and PsbQ but also a part of PsbO from Euglena PSII, indicating that PsbO binds to Euglena PSII more loosely than those of other organisms. Treatments by urea/NaCl, alkaline Tris or CaCl2 completely removed the three extrinsic proteins from Euglena PSII. (3) Each of the Euglena extrinsic proteins bound directly to PSII independent of the other extrinsic proteins, which is similar to the binding properties of the extrinsic proteins in a green alga, Chlamydomonas reinhardtii. (4) One of the significant features of Euglena PSII is that the oxygen evolution was not enhanced by Ca2+. When CaCl2-treated Euglena PSII was reconstituted with PsbO, the oxygen-evolving activity was stimulated by the addition of NaCl, but no further stimulation was observed by CaCl2. (5) Oxygen evolution of Euglena PSII reconstituted with PsbO from C. reinhardtii or spinach instead of that from Euglena also showed no enhancement by Ca2+, whereas a significant enhancement of oxygen evolution was observed by Ca2+ when the green algal or higher plant PSII was reconstituted with Euglena PsbO instead of their own PsbO. These results indicate that the PSII intrinsic proteins instead of the extrinsic PsbO protein, are responsible for the stimulation of oxygen evolution by Ca2+. Sequence comparison of major PSII intrinsic proteins revealed that PsbI of Euglena PSII is remarkably different from other organisms in that Euglena PsbI possesses extra 16-17 residues exposed to the luminal side. This may be related to the loss of enhancement of oxygen evolution by Ca2+ ion.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
0032-0781
pubmed:author
pubmed:issnType
Print
pubmed:volume
45
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1168-75
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2004
pubmed:articleTitle
Isolation and characterization of oxygen-evolving photosystem II complexes retaining the PsbO, P and Q proteins from Euglena gracilis.
pubmed:affiliation
Department of Biology, Faculty of Science, Tokyo University of Science, Kagurazaka 1-3, Shinjuku-ku, Tokyo, 162-8601 Japan.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't