STRUCTURAL-PROPERTIES OF THE OUTER-MEMBRANE AND THE REGULAR SURFACE PROTEIN OF COMAMONAS-ACIDOVORANS

The outer membrane of Comamonas acidovorans, formerly Pseudomonas acidovorans, contains a regularly arrayed surface protein. The tetragonal lattice (p4 symmetry, unit cell dimensions a = b = 10.5 nm is composed of a single type of polypeptide. It forms dimeric morphological complexes as revealed by means of electron microscopy in conjunction with image processing, STEM mass determination, and IR analysis. The surface protein has tightly associated carbohydrates and behaves like a glycoprotein in electrophoresis and IR spectroscopy. The outer membrane proteins Omp21 and Omp32 are not regularly arrayed. Omp32 has the characteristic attributes of an intrinsic outer membrane protein, such as moderate hydrophobicity, a high β-structure content, and a typical solubilization behavior. It forms channels in black lipid membranes and it, therefore, represents the major porin of C. acidovorans. © 1990.