A trehalose biosynthetic enzyme doubles as an osmotic stress sensor to regulate bacterial morphogenesis

A trehalose biosynthetic enzyme doubles as an osmotic stress sensor to regulate bacterial morphogenesis

The dissacharide trehalose is an important intracellular osmoprotectant and the OtsA/B pathway is the principal pathway for trehalose biosynthesis in a wide range of bacterial species. Scaffolding proteins and other cytoskeletal elements play an essential role in morphogenetic processes in bacteria. Here we describe how OtsA, in addition to its role in trehalose biosynthesis, functions as an os...

Bacterial glycoengineering as a biosynthetic route to customized glycomolecules

Bacterial responses to osmotic challenges

Microbes respond to osmotic challenges in diverse, variable, and extreme natural environments Exposure to diverse environments is a hallmark of microbial life. Microbes are everywhere; collectively, microbes experience everything. They live inside and outside eu-karyotic hosts, in soil, water, and air at diverse planetary sites. They may exist as individuals (planktonic growth) or aggregates, a...

A Stress Sensor for the Bacterial Periplasm

DegS, the periplasmic stress sensor, becomes activated when its PDZ domain recognizes the improperly exposed C-terminal sequences of outer membrane porins. This interaction relieves the inhibition of the neighboring protease domain of DegS, triggering a proteolysis cascade that leads to the sigma(E)-driven expression of periplasmic chaperones.

Allosteric Activation of a Bacterial Stress Sensor

In Gram-negative bacteria, envelope stress signals such as unfolded outer membrane proteins (OMP) activate the periplasmic protease DegS. This protease then triggers a cellular pathway to alleviate the stress. Now Sohn et al. (2007) show conclusively that inhibition of DegS is relieved allosterically by binding of the C-terminal sequences in unfolded OMPs to the PDZ domain of DegS.