Linked Life Data

16023363

Source:http://linkedlifedata.com/resource/pubmed/id/16023363

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
9
pubmed:dateCreated
2005-8-22
pubmed:abstractText
We have developed a method for rapidly quantifying the extent to which the functionally important Met144 and Met145 residues near the C-terminus of calmodulin (CaM) are converted to the corresponding sulfoxides, Met(O). The method utilizes a whole protein collision-induced dissociation (CID) approach on an electrospray ionization quadrupole time-of-flight (ESI-Q-TOF) mass spectrometer. Using standards of CaM oxidized by hydrogen peroxide (H2O2) or peroxynitrite (ONOO-), we demonstrated that CID fragmentation of the protein ions resulted in a series of C-terminal singly charged y1-y15 ions. Fragments larger than y4 exhibited mass shifts of +16 or +32 Da, corresponding to oxidation of one or two methionines, respectively. To assess the extent of oxidative modification for Met144 and Met145 to Met(O), we averaged the ratio of intensities for yn, yn+16, and yn+32 ions, where n=6-9. By alternating MS and CID scans at low and high collision energies, this technique allowed us to rapidly determine both the distribution of intact CaM oxiforms and the extent of oxidative modification in the C-terminal region of the protein in a single run. We have applied the method to studies of the repair of fully oxidized CaM by methionine sulfoxide reductases (MsrA and MsrB), which normally function in concert to reduce the S and R stereoisomers of methionine sulfoxide. We found that repair of Met(O)144 and Met(O)145 did not go to completion, but was more efficient than average Met repair. Absence of complete repair is consistent with previous studies showing that accumulation of methionine sulfoxide in CaM can occur during aging (Gao, J.; Yin, D.; Yao, Y.; Williams, T. D.; Squier, T. C. Biochemistry1998, 37, 9536-9548).
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
1044-0305
pubmed:author
pubmed:issnType
Print
pubmed:volume
16
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1470-80
pubmed:dateRevised
2007-12-3
pubmed:meshHeading
pubmed:year
2005
pubmed:articleTitle
Rapid method for quantifying the extent of methionine oxidation in intact calmodulin.
pubmed:affiliation
Mass Spectrometry Laboratory, University of Kansas, Lawrence, Kansas 66045-7582, USA.
pubmed:publicationType
Journal Article, Evaluation Studies, Research Support, N.I.H., Extramural