Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
25
pubmed:dateCreated
1996-8-20
pubmed:abstractText
The role of the N-terminal region of tobacco Rubisco activase in ATP hydrolysis and ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) activation was examined by construction of mutant proteins. Deletion of the first 50 amino acids of Rubisco activase almost completely eliminated the ability to activate Rubisco, without changing the ATP-hydrolyzing and self-associating properties of the enzyme. Thus, the N-terminus of Rubisco activase is distinct from the ATP-hydrolyzing domain and is required for Rubisco activation. Directed mutagenesis of the species-invariant tryptophan residue at position 16 inhibited Rubisco activation but not the binding or hydrolysis of ATP. The ability to activate Rubisco was less severely inhibited when Trp was replaced by a Tyr or Phe than by an Ala or Cys, indicating that an aromatic residue at position 16 and particularly a Trp is required for proper activation of Rubisco. Fluorescence quenching of the 7-nitrobenz-2-oxa-1,3-diazole-modified W16C mutant upon addition of nucleotide suggested that position 16 becomes more solvent accessible in response to nucleotide binding. However, changes in the intrinsic fluorescence of truncated and Trp16 mutants upon addition of ATP were similar to those of the wild type, evidence that Trp16 is not the residue reporting the conformational change that accompanies subunit association.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
25
pubmed:volume
35
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
8143-8
pubmed:dateRevised
2004-2-9
pubmed:meshHeading
pubmed:year
1996
pubmed:articleTitle
Activation of ribulose-1,5-biphosphate carboxylase/oxygenase (Rubisco) involves Rubisco activase Trp16.
pubmed:affiliation
United States Department of Agriculture, Agricultural Research Service, Western Cotton Research Laboratory, Phoenix, Arizona 85040-8830, USA.
pubmed:publicationType
Journal Article