SEDS proteins are a widespread family of bacterial cell wall polymerases

Summary Elongation of rod-shaped bacteria is mediated by a dynamic peptidoglycan synthetic machinery called the Rod complex. We report that in Bacillus subtilis this complex is functional in the absence of all known peptidoglycan polymerases. Cells lacking these enzymes survive by inducing an envelope stress response that increases expression of RodA, a widely conserved core component of the Rod complex. RodA is a member of the SEDS family of proteins that play essential but ill-defined roles in cell wall biogenesis during growth, division and sporulation. Our genetic and biochemical analyses indicate that SEDS proteins constitute a new family of peptidoglycan polymerases. Thus, B. subtilis and likely most bacteria use two distinct classes of polymerases to synthesize their exoskeleton. Our findings indicate that SEDS family proteins are core cell wall synthases of the cell elongation and division machinery, and represent attractive targets for antibiotic development

Verrucomicrobial Methanotrophs

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Physiology and Biochemistry of the Aerobic Methanotrophs

Methanotrophs are a widely distributed group of aerobic bacteria that use methane as their source of carbon and energy. They play key roles in the global carbon cycle, including controlling anthropogenic and natural emissions of the greenhouse gas methane. Methanotrophs oxidize methane using the unique enzyme methane monooxygenase which exists in two structurally and biochemically distinct forms. One form, the membrane-associated or particulate methane monooxygenase (pMMO), is found in most known methanotrophs and is located in the cytoplasmic membrane. Another form, the soluble methane monooxygenase (sMMO), is found in some methanotrophs and is located in the cytoplasm. Both forms of MMO can co-oxidize a range of hydrocarbons and chlorinated pollutants and hence are interesting with respect to the biotechnological potential of methanotrophs. Methanol is further oxidized to formaldehyde, formate, and CO2, by specific methylotrophic enzymes, while biomass is built from formaldehyde, formate, CO2, or a combination thereof via three cyclic biochemical pathways: the ribulose monophosphate (RuMP) cycle, the serine pathway, and the Calvin-Benson-Bassham (CBB) cycle. The availability of genome sequences of methanotrophs enables postgenomic studies to investigate the regulation of methane oxidation in the laboratory and in the environment by natural methanotrophs and in laboratory or industrial conditions by platform organisms. Recent studies have included synthetic biology approaches and in future may incorporate the design of new pathways