An invariant C-terminal tryptophan in McdB mediates its interaction and positioning function with carboxysomes.

Bacterial microcompartments (BMCs) are widespread, protein-based organelles that regulate metabolism. The model for studying BMCs is the carboxysome, which facilitates carbon fixation in several autotrophic bacteria. Carboxysomes can be distinguished as type α or β, which are structurally and phyletically distinct.

Dissecting the phase separation and oligomerization activities of the carboxysome positioning protein McdB.

Across bacteria, protein-based organelles called bacterial microcompartments (BMCs) encapsulate key enzymes to regulate their activities. The model BMC is the carboxysome that encapsulates enzymes for CO fixation to increase efficiency and is found in many autotrophic bacteria, such as cyanobacteria. Despite their importance in the global carbon cycle, little is known about how carboxysomes are spatially regulated.

Cell surface-localized CsgF condensate is a gatekeeper in bacterial curli subunit secretion.

Curli are functional amyloids present on the outer membrane of E. coli. CsgF is required for the proper assembly of curli.

Polyphosphate drives bacterial heterochromatin formation.

Heterochromatin is most often associated with eukaryotic organisms. Yet, bacteria also contain areas with densely protein-occupied chromatin that appear to silence gene expression. One nucleoid-associated silencing factor is the conserved protein Hfq.

The McdAB system positions α-carboxysomes in proteobacteria.

Carboxysomes are protein-based organelles essential for carbon fixation in cyanobacteria and proteobacteria. Previously, we showed that the cyanobacterial nucleoid is used to equally space out β-carboxysomes across cell lengths by a two-component system (McdAB) in the model cyanobacterium Synechococcus elongatus PCC 7942. More recently, we found that McdAB systems are widespread among β-cyanobacteria, which possess β-carboxysomes, but are absent in α-cyanobacteria, which possess structurally and phyletically distinct α-carboxysomes.

Expanding Tiny Earth to genomics: a bioinformatics approach for an undergraduate class to characterize antagonistic strains.

The evolution of multidrug resistant pathogens and the diminishing supply of effective antibiotics are global crisis. Tiny Earth (TE) is undergraduate curriculum that encourage students to pursue science careers by engagement in authentic drug discovery research. Through the TE program, students identify environmental strains that inhibit other bacteria.

Origin and Evolution of Carboxysome Positioning Systems in Cyanobacteria.

Carboxysomes are protein-based organelles that are essential for allowing cyanobacteria to fix CO2. Previously, we identified a two-component system, McdAB, responsible for equidistantly positioning carboxysomes in the model cyanobacterium Synechococcus elongatus PCC 7942 (MacCready JS, Hakim P, Young EJ, Hu L, Liu J, Osteryoung KW, Vecchiarelli AG, Ducat DC. 2018.

Loci Encoding Compounds Potentially Active against Drug-Resistant Pathogens amidst a Decreasing Pool of Novel Antibiotics.

Since the discovery of penicillin, microbes have been a source of antibiotics that inhibit the growth of pathogens. However, with the evolution of multidrug-resistant (MDR) strains, it remains unclear if there is an abundant or limited supply of natural products to be discovered that are effective against MDR isolates. To identify strains that are antagonistic to pathogens, we examined a set of 471 globally derived environmental strains (env-Ps) for activity against a panel of 65 pathogens including spp.