ppGpp
Research Article | Molecular Biology and PhysiologyPosttranslational Control of PlsB Is Sufficient To Coordinate Membrane Synthesis with Growth in Escherichia coliHow do bacterial cells grow without breaking their membranes? Although the biochemistry of fatty acid and membrane synthesis is well known, how membrane synthesis is balanced with growth and metabolism has remained unclear. This is partly due to the many control points that have been discovered within the membrane synthesis pathways. By precisely establishing the contributions of individual pathway enzymes, our results simplify the...
Editor's Pick Research Article | Molecular Biology and PhysiologyTailoring a Global Iron Regulon to a UropathogenHost iron restriction is a common mechanism for limiting the growth of pathogens. We compared the regulatory network controlled by Fur in uropathogenic E. coli (UPEC) to that of nonpathogenic E. coli K-12 to uncover strategies that pathogenic bacteria use to overcome iron limitation. Although iron...
Editor's Pick Research Article | Molecular Biology and PhysiologyThe Absence of (p)ppGpp Renders Initiation of Escherichia coli Chromosomal DNA Synthesis Independent of Growth RatesBacterial cells regulate their own chromosomal DNA synthesis and cell division depending on the growth conditions, producing more DNA when growing in nutritionally rich media than in poor media (i.e., human gut versus water reservoir). The accumulation of the nucleotide analog (p)ppGpp is usually viewed as serving to warn cells of impending peril due to otherwise lethal sources of stress, which stops growth and inhibits DNA, RNA, and...
Research Article | Molecular Biology and PhysiologyThe Stringent Response Inhibits DNA Replication Initiation in E. coli by Modulating Supercoiling of oriCTo survive bouts of starvation, cells must inhibit DNA replication. In bacteria, starvation triggers production of a signaling molecule called ppGpp (guanosine tetraphosphate) that helps reprogram cellular physiology, including inhibiting new rounds of DNA replication. While ppGpp has been known to block replication initiation in Escherichia coli for decades, the...
Research Article | Molecular Biology and PhysiologySerine-Threonine Kinases Encoded by Split hipA Homologs Inhibit Tryptophanyl-tRNA SynthetaseBacterial toxin-antitoxin (TA) modules confer multidrug tolerance (persistence) that may contribute to the recalcitrance of chronic and recurrent infections. The first high-persister gene identified was hipA of Escherichia coli strain K-12, which encodes a kinase that inhibits glutamyl-tRNA synthetase. The hipA gene encodes the toxin of the hipBA...