Linked Life Data

11742763

Source:http://linkedlifedata.com/resource/pubmed/id/11742763

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
2001-12-14
pubmed:abstractText
Two proteins of Klebsiella pneumoniae, termed Yor5 and Yco6, were analyzed for their capacity to participate in the reversible phosphorylation of proteins on tyrosine. First, protein Yco6 was overproduced from its specific gene and purified to homogeneity by affinity chromatography. Upon incubation in the presence of radioactive adenosine triphosphate, it was found to effectively autophosphorylate. Two-dimensional analysis of its phosphoamino acid content revealed that it was modified exclusively at tyrosine. Second, protein Yor5 was also overproduced from the corresponding gene and purified to homogeneity by affinity chromatography. It was shown to contain a phosphatase activity capable of cleaving the synthetic substrate p-nitrophenyl phosphate into p-nitrophenol and free phosphate. In addition, it was assayed on individual phosphorylated amino acids and appeared to dephosphorylate specifically phosphotyrosine, with no effect on phosphoserine or phosphothreonine. Such specificity for phosphotyrosine was confirmed by the observation that Yor5 was able to dephosphorylate protein Yco6 previously autophosphorylated. Together, these data demonstrate that similarly to other bacterial species including Acinetobacter johnsonii and Escherichia coli, the cells of K. pneumoniae contain both a protein-tyrosine kinase and a phosphotyrosine-protein phosphatase. They also provide evidence that this phosphatase can utilize the kinase as an endogenous substrate, which suggests the occurrence of a regulatory mechanism connected with reversible protein phosphorylation on tyrosine. Since Yco6 and Yor5 are both involved in the synthesis of capsular polysaccharide and since capsules are essential to the virulence of K. pneumoniae, we suggest that reversible protein phosphorylation on tyrosine may be part of the cascade of reactions that determine the pathogenicity of bacteria.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
1096-4959
pubmed:author
pubmed:issnType
Print
pubmed:volume
131
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
103-12
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed:year
2002
pubmed:articleTitle
Isolation and characterization of a protein-tyrosine kinase and a phosphotyrosine-protein phosphatase from Klebsiella pneumoniae.
pubmed:affiliation
Institut de Biologie et Chimie des Protéines, Centre National de la Recherche Scientifique, Lyon, France.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't