Biochemical characterization of evasion from peptidoglycan recognition by Staphylococcus aureus D-alanylated wall
Kenji Kurokawa1, Ji-Hee Gong, Kyoung-Hwa Ryu
1The National Research Laboratory of Defense Proteins, College of Pharmacy, Pusan National University, Busan, Republic of Korea.
Abstract:
We recently reported that D-alanylation of Staphylococcus aureus wall teichoic acid (WTA) mitigates an induction of the Toll-mediated humoral response in Drosophila by interfering with peptidoglycan (PG) recognition by PG recognition protein-SA (PGRP-SA). Here, we investigated the mode of this interference by using an in vitro cell free system from larvae of the coleoptran insect Tenebrio molitor. WTA modification on PG had a potent inhibitory effect on PGRP-SA-mediated Toll proteolytic cascade activation, and the D-alanylation of WTA enhanced its inhibitory effect. Purified D-alanylated WTA released from PG lost its inhibitory action on both Toll cascade activation and PGRP-SA binding to insoluble PG. The inhibition of PGRP-SA binding to PG by D-alanylated WTA took place not only on polymeric PG but also on WTA-attached disaccharide units of monomeric PG. These results suggest that D-alanylation-mediated evasion requires the covalent bonding of D-alanylated WTA to PG, but not net-like cross-linking structure of PG.
Related Concept Videos
Archaeal Cell Wall
Bacterial Cell Wall
Defense Against Bacterial Pathogens
Phagocytes
Phagocytes are the frontline soldiers of the immune system. They include neutrophils and macrophages. Neutrophils are the most abundant type of white blood cell and are quickly mobilized to the site of infection. Macrophages are larger cells that patrol...
Inhibitors of Gram-positive Cell Wall Synthesis
Peptidoglycan Synthesis
Defenses Against Pathogens and Herbivores


