His6-Cdc48a and associated proteins purified from H. volcanii. A) SDS- PAGE of proteins purified by Ni2+ -chromatography. H. volcanii carrying empty vector control (H1209-pJAM202c, lane 1) and ectopically expressing His6-Cdc48a (H1209- pJAM1409, lane 2). Red bars indicate regions of gel excised. B) Proteins identified in gel slices by LC-MS/MS analysis. Criteria for protein inclusion: FDR < 0.01%, normalized total spectra minus control > 50, protein threshold > 99% and 2 peptide minimum. Based on spectral counting, Cdc48a and DUF111 were most abundant in regions (a) and (b), respectively, as indicated. DHS1, deoxyhypusine synthase. DUF111, Cdc48a gene neighbor of unknown function. TnaA, tryptophanase; Rps3, ribosomal protein S3; n.d., not detected.