Functional Plasticity of the AgrC Receptor Histidine Kinase Required for Staphylococcal Virulence.

Staphylococcus aureus employs the receptor histidine kinase (RHK), AgrC, to detect quorum-sensing (QS) pheromones, the autoinducer peptides (AIPs), which regulate the virulence of the bacterium. Variation in the QS circuit divides S. aureus into four subgroups, each producing a specific AIP-AgrC pair.

Revealing Higher Order Protein Structure Using Mass Spectrometry.

The development of rapid, sensitive, and accurate mass spectrometric methods for measuring peptides, proteins, and even intact protein assemblies has made mass spectrometry (MS) an extraordinarily enabling tool for structural biology. Here, we provide a personal perspective of the increasingly useful role that mass spectrometric techniques are exerting during the elucidation of higher order protein structures. Areas covered in this brief perspective include MS as an enabling tool for the high resolution structural biologist, for compositional analysis of endogenous protein complexes, for stoichiometry determination, as well as for integrated approaches for the structural elucidation of protein complexes.

Modified Clp protease complex in the ClpP3 null mutant and consequences for chloroplast development and function in Arabidopsis.

The plastid ClpPRT protease consists of two heptameric rings of ClpP1/ClpR1/ClpR2/ClpR3/ClpR4 (the R-ring) and ClpP3/ClpP4/ClpP5/ClpP6 (the P-ring) and peripherally associated ClpT1/ClpT2 subunits. Here, we address the contributions of ClpP3 and ClpP4 to ClpPRT core organization and function in Arabidopsis (Arabidopsis thaliana). ClpP4 is strictly required for embryogenesis, similar to ClpP5.