Insights into pneumococcal fratricide: The first structure of a pneumococcal autolysin, LytC
Project Leader: Juan A. Hermoso

LytC The first structure of a pneumococcal autolysin, that of LytC, has been solved in ternary complex with choline and a pneumococcal peptidoglycan fragment. The active site of the hydrolase module is not fully exposed but oriented towards the choline-binding module accounting for its unique in vivo features in peptidoglycan hydrolysis, its activation and its regulatory mechanisms. Due to the unusual hook-shaped conformation of the multimodular protein, it is only able to hydrolyze non-crosslinked peptidoglycan chains, an assertion validated by additional experiments. These results explain the activation of LytC by CbpD in fratricide, a competence-programmed mechanism of predation of noncompetent sister cells. The results provide the first structural insights into the critical and central function that LytC plays in pneumococcal virulence and explain a long-standing puzzle of how murein hydrolases can be controlled to avoid self-lysis during bacterial growth and division.

References:

Pérez-Dorado, I; González, A; Morales, M; Sanles, R; Striker, W; Vollmer, W; Mobashery, S; García, JL; Martínez-Ripoll, M; García, P; Hermoso, JA
Nature Structural & Molecular Biology (2010) 17, 576-582 (doi:10.1038/nsmb.1817)



Enjoy the short movie shown below, explaining how CbpD activates LytC in fratricide...