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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
2003-12-23
pubmed:abstractText
A multi-technique approach to identification and mapping of phosphorylation on protein kinase A (PKA) is described. X-ray crystallography revealed phosphorylation at T197 and S338 while mass spectrometry (MS) on the intact protein suggested phosphorylation at three sites. Tryptic digestion, followed by MS, confirmed the presence of three phosphates. However, metal affinity treatment of the digest prior to MS revealed the presence of a fourth phosphopeptide. Subsequent analysis of the digests using liquid chromatography (LC) coupled with quadrupole ion trap (QIT) MS confirmed phosphorylation at S10 and S338 and suggested phosphorylation at S139 and T195/197. Unfortunately, identification of pS139 was inconclusive due to low signal intensity and early elution in reversed-phase LC while poor MS/MS data prevented localization of the phosphate to T195 or T197. Phosphopeptide modification with ethanethiol, followed by LC QIT-MS/MS, identified four phosphopeptides in a single experiment. In addition, the fragmentation data provided significantly more sequence information than data obtained from unmodified peptides. Data from this study suggested that PKA was completely phosphorylated at S10, T197, and S338 and partially phosphorylated at S139. These results illustrate that critical information can be lost unless multiple MS techniques are used for identification and validation of phosphorylation.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
0003-2697
pubmed:author
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
324
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
204-18
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed:year
2004
pubmed:articleTitle
Characterization of protein kinase A phosphorylation: multi-technique approach to phosphate mapping.
pubmed:affiliation
Abbott Laboratories, Department of Structural Chemistry, 200 Abbott Park Road, Abbott Park, IL 60064, USA.
pubmed:publicationType
Journal Article