Molecular Organization of the Rigid Layer and the Cell Wall of Escherichia coli

Publisher Website
Google Scholar
Abstract
A model for the supermolecular structure of the rigid layer (murein-lipoprotein complex) of the cell wall of Escherichia coli was devised, based on chemical structure analysis. According to these data, 250,000 lipoprotein molecules of known amino-acid sequence are evenly distributed over a one-layered murein net. The sequence and conformation of the lipoprotein is unusual. The murein net consists of polysaccharide chains cross-linked by short peptides. Since one disaccharide unit of the polysaccharide chains is probably 10.3 A long, the lipoprotein molecules, hooked statistically to every 10th–12th disaccharide unit, are spaced 100–120 A apart. The distance from center to center of neighboring polysaccharide chains is 12–13 A. From this rather precise view of the distribution of the lipoprotein molecules on the net, a model can be presented for the basic arrangement of the wall. Immunologic studies show that the lipoprotein protrudes from the innermost part of the wall towards the surface, and it is likely that it plays mainly a structural role. Due to the hydrophilic and hydrophobic properties of the lipoprotein, the other main components of the wall (e.g., lipopolysaccharide, phospholipids, proteins) could be organized around the lipoprotein molecules so that these could form the covalently anchored core of subunits of which the cell wall is built.

This publication has 0 references indexed in Scilit: