More than just lysins: peptidoglycan hydrolases tailor the cell wall.

Enzymes that degrade the peptidoglycan(PG) cell wall layer called PG hydrolasesor autolysinsare often thought of as destructive forces. Phages employ them to lyse their host for the release of virion particles and some bacteria secrete them to eliminate (lyse) their competition. However, bacteria also harness the activity of PG hydrolasesfor important aspects of growth, division, and development. Of course, using PG hydrolasesin this capacity requires that they be tightly regulated. While this has been appreciated for some time, we are only just beginning to understand the mechanisms governing the activities of these ‘tailoring’ enzymes. This review will focus on recent advances in this area with an emphasis on the regulation of PG hydrolasesinvolved in cell division.