The l Endolysin and Endolysins in General

l R is an 18 kDa soluble transglycosylase, which cleaves the glycosidic bond between N-acetylglucosamine and N-acetyl-muramic acid resiues, forming a cyclic product (15). Its crystal structure reveals that it is evolutionarily related to true lysozymes, which hydrolyze the same bond (43). R appears to be dependent on the holin for crossing the membrane, although at about 3 hours after induction some R-dependent lysis of ISam-infected cells does begin to occur (R.Young, unpublished data).Whether this reflects an intrinsic membrane-penetrating ability of R or low-level access to the sec system is unclear. The N and C termini of R are surface-exposed in crystal structures (43), a structural feature exploited to construct fusion proteins for probing the size of the "hole" (see below).

0 0

Post a comment