The marine nitrogen fixing microorganisms (diazotrophs) are a major source of nitrogen to open ocean ecosystems and are predicted to be limited by iron in most marine environments. Here we use global and targeted proteomic analyses on a key unicellular marine diazotroph Crocosphaera watsonii to reveal large scale diel changes in its proteome, including substantial variations in concentrations o...

Lipid A is the hydrophobic anchor of lipopolysaccharide (LPS) and forms the major lipid component of the outer monolayer of the outer membrane of gram-negative bacteria. Lipid A is required for bacterial growth and virulence, and inhibition of its biosynthesis is lethal to bacteria. UDP-3-O-(R-3-hydroxymyristoyl)-N-acetylglucosamine deacetylase (LpxC) is a metalloenzyme that catalyzes the secon...

The hammerhead ribozyme was first considered as a metalloenzyme despite persistent inconsistencies between structural and functional data. In the last decade, metal ions were confirmed as catalysts in self-splicing ribozymes but displaced by nucleobases in self-cleaving ribozymes. However, a model of catalysis just relying on nucleobases as catalysts does not fully fit some recent data. Gatheri...

Pseudomonas aeruginosa (PA) plays plays an important role in nosocomial infection. To explore the heteroresistance of PA to imipenem (IMP), we detected the sensitivity of 140 strains of PA to IMP using the KB method and VITEK method. Combined with resistance mutation analysis, the heteroresistance of PA to IMP was determined. Whilst, the double disk synergy test and SYBGreen RT-PCR for efflux p...

The potent vasodilatory peptide bradykinin is cleaved at the Phe5-Ser6 bond in vitro by the metalloenzyme endopeptidase-24.15 (E.C.3.4.24.15). We now report that intravenous infusion of N-[1-(R,S)-carboxy-3-phenylpropyl]-Ala-Ala-Phe-p-aminobenzoate, a specific active site-directed inhibitor of endopeptidase-24.15, produces an immediate drop in mean arterial pressure of as much as 50 mm Hg in pe...