Peptidoglycan hydrolases, bacterial shape, and pathogenesis

• Peptidoglycan (PG) hydrolases cleave the PG sacculus.
• PG hydrolase activity can dramatically affect bacterial shape.
• Bacterial shape and PG hydrolase modification can alter pathogenic properties.
• Hydrolases are highly regulated.

Bacterial shape has always been hypothesized to play an important role in the biology of a species and in the ability of certain bacteria to influence human health. The recent discovery of peptidoglycan hydrolases that modulate shape has now allowed this hypothesis to be addressed directly. Genetic, biochemical, and phenotypic studies have found that changes in shape and underlying peptidoglycan structure influence many pathogenic attributes including surviving unfavorable conditions, predation, transmission, colonization, and host interactions. The diversity of bacterial shapes, niches, and lifestyles is also reflected in diverse mechanisms of hydrolase regulation, critical for maintaining peptidoglycan integrity and biological properties of the cell. Future studies will build on the current work described and further elucidate the intersection of peptidoglycan hydrolase activity, shape, and disease outcome.