Linked Life Data

11278626

Source:http://linkedlifedata.com/resource/pubmed/id/11278626

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
16
pubmed:dateCreated
2001-4-17
pubmed:abstractText
In the chlorophyte Selenastrum minutum, phosphoenolpyruvate carboxylase (PEPC) exists as two kinetically distinct classes of isoforms sharing the same 102-kDa catalytic subunit (p102). Class 1 PEPC is homotetrameric, whereas Class 2 PEPCs consist of three large protein complexes. The different Class 2 PEPCs contain p102 and 130-, 73-, and 65-kDa polypeptides in different stoichiometric combinations. Immunoblot, immunoprecipitation, and chemical cross-linking studies indicated that p102 physically interacts with the 130-kDa polypeptide (p130) in Class 2 PEPCs. Immunological data and mass spectrometric and sequence analyses revealed that p102 and p130 are not closely related even if a p130 tryptic peptide had significant similarity to a conserved PEPC C-terminal domain from several sources. Evidence supporting the hypothesis that p130 has PEPC activity includes the following. (i) Specific activity expressed relative to the amount of p102 was lower in Class 1 than in Class 2 PEPCs; (ii) reductive pyridoxylation of both p102 and p130 was inhibited by magnesium-phosphoenolpyruvate; and (iii) biphasic phosphoenolpyruvate binding kinetics were observed with Class 2 PEPCs. These data support the view that unicellular green algae uniquely express, regulate, and assemble divergent PEPC polypeptides. This probably serves an adaptive purpose by poising these organisms for survival in different environments varying in nutrient content.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
20
pubmed:volume
276
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
12588-97
pubmed:dateRevised
2010-11-18
pubmed:meshHeading
pubmed:year
2001
pubmed:articleTitle
Two unrelated phosphoenolpyruvate carboxylase polypeptides physically interact in the high molecular mass isoforms of this enzyme in the unicellular green alga Selenastrum minutum.
pubmed:affiliation
Department of Plant Science, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada. rivoalj@ms.umanitoba.ca
pubmed:publicationType
Journal Article, Comparative Study, Research Support, Non-U.S. Gov't