ISOLATION AND CHARACTERIZATION OF MAJOR OUTER-MEMBRANE PROTEINS OF PSEUDOMONAS-AERUGINOSA STRAIN PAO WITH SPECIAL REFERENCE TO PEPTIDOGLYCAN-ASSOCIATED PROTEIN

The outer membrane of P. aeruginosa PAO contains 6 major proteins (proteins D, E, F, G, H and I). Two of them (protein F and protein H) were retained by the peptidoglycan layer when cell envelopes were extracted with 2% sodium dodecyl sulfate (SDS) solution at 35.degree. C. At higher temperatures (> 55.degree. C), no proteins were retained by peptidoglycan. Using this property, purification of protein F and protein H was achieved. Three other major outer membrane proteins, D, E and I, were also isolated and characterized. Their amino acids compositions were determined. Circular dichroism spectra of these isolated proteins were measured in SDS solution. Protein F was rich in .beta.-structure, while protein I was rich in .alpha.-helix. When isolated protein F was heated (100.degree. C, 15 min) in SDS solution, the circular dichroism spectrum changed significantly. In parallel with the conformational change, the electrophoretic mobility of protein F on urea-SDS polyacrylamide gel also changed. Protein F evidently is a heat-modifiable protein.