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Identification of covalent modification of SecA


EMSL Project ID
2537

Abstract

SecA is the peripherally membrane-bound ATPase that is part of the translocon that mediates the export of proteins from the bacterial cytoplasm and outer membrane. In vivo 50% of the SecA is found membrane associated and the remainder is free in the cytosol. We have purified SecA from both fractions and found that they differ in their solution behavior. Both exist as dimmers but they have different Keq for the monomer-dimer equilibrium. We have also shown that there are multiple forms in each population. Isoelectric focusing shows that the pI for the membrane forms is more acidic. We need to determine what modification is causing these differences. After we know what the covalent modification is we will determine its physiological significance. We will send two versions of SecA proteins: unlabeled and N15 labeled. Trypsin digestion will be performed on the mixture of these proteins and LC/MS and LC/MS/MS experiments will be performed on 7 T FTICR MS. Data analysis may show the differences between proteins.

Project Details

Project type
Exploratory Research
Start Date
2002-05-20
End Date
2003-10-27
Status
Closed

Team

Principal Investigator

Linda Randall
Institution
University of Missouri - Columbia