Multisite Process Research Articles

Elongation of the murein sacculus of Escherichia coli

Elongation is an orderly multisite process in which, at each of about 90 growth points, two strands of murein are concurrently being synthesized, inserted and cross-linked to the sacculus. The enzymes involved move around the circumference of the cytoplasmic membrane at a rate of about 5 nm per second as new strands are being inserted, and this rate is sufficient to double the length of the cell during the cell division cycle.

Evidence for diffuse growth of the cylindrical portion of the Escherichia coli murein sacculus.

High-resolution autoradiography of thin sections of Escherichia coli cells whose murein was pulse-labeled with [3H]diaminopimelic acid after a period of diaminopimelic acid deprivation indicated that elongation of the murein sacculus occurs by a multisite (diffuse) process. Upon chasing, radioactivity in polar murein was stable, whereas radioactivity in cylindrical murein was reduced, indicating that diffuse intercalation of new murein occurred during cell elongation. Elongation and septation were shown to be overlapping processes.