2D-PAGE gel electrophoresis of polyP-deficient and control Pseudomonas sp . B4 cell. Colonies from Pseudomonas sp. B4 polyP-deficient and control cells were grown in LB medium for 48 h. Samples were prepared and analyzed as described in Methods. The upper panels show the separation of proteins in the 5-8 pH range. To have a better resolution of some protein spots a 4.7-5.9 pH range was used (lower panels). Numbers with arrows indicate the spot numbers used for MS/MS analyses (Tables 1 and 2).