Degradation of Spore Peptidoglycan During Germination
David L. Popham, Jared D. Heffron and Emily A. Lambert
from: Bacterial Spores: Current Research and Applications (Edited by: Ernesto Abel-Santos). Caister Academic Press, U.K. (2012)
During spore germination, several spore components are broken down and are discarded or recycled. The first major degradative step in germination is depolymerization of the spore cortex peptidoglycan. This is essential to allow full hydration of the spore core and the resumption of cellular metabolism. The spore cortex is a thick layer of peptidoglycan with structural modifications that differentiate it from vegetative cell wall material. Germination-specific cortex lytic enzymes exhibit specificity for the muramic-δ-lactam modification of the peptidoglycan strands. As no protein synthesis can take place during germination prior to cortex breakdown, the cortex lytic enzymes must be produced during spore formation and packaged within the dormant spore in an inactive and highly stable form. A mechanism(s) must then exist for the activation of lytic enzymes during germination. This chapter will cover the current knowledge concerning the identities of cortex lytic enzymes in Bacilli and Clostridia, their expression and incorporation into dormant spores, the mechanisms that hold them inactive during spore dormancy and their activation during germination, and their specific lytic activities, substrates, and products read more ...