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Research has been conducted on the ATP:corrinoid adenosyltransferase from Salmonella typhimurium. The X-ray structure of this adenosyltransferase in its substrate-free state complexed with MgATP and in the ternary complex with CobA and MgATP has been investigated.

Research demonstrates that cob(III)alamin reductase enzyme may be absent in the Salmonella enterica serovar Typhimurium LT2. Data indicate that reduced flavin nucleotides help the bacterium maintain nonadenosylated cobalmin and corrinoids as co(II)rrinoids in vivo.

The Gram-negative bacterium Legionella pneumophila is ubiquitous in freshwater environments as a free-swimming organism, resident of biofilms, or parasite of protozoa. If the bacterium is aerosolized and inhaled by a susceptible human host, it can infect alveolar macrophages and cause a severe pneumonia known as Legionnaires' disease. A sophisticated cell differentiation program equips L. pneumophila to persist in both extracellular and intracellular niches. During its life cycle, L. pneumophila alternates between at least two distinct forms: a transmissive form equipped to infect host cells and evade lysosomal degradation, and a replicative form that multiplies within a phagosomal compartment that it has retooled to its advantage. The efficient changeover between transmissive and replicative states is fundamental to L. pneumophila's fitness as an intracellular pathogen. The transmission and replication programs of L. pneumophila are governed by a number of metabolic cues that signal whether conditions are favorable for replication or instead trigger escape from a spent host. Several lines of experimental evidence gathered over the past decade establish strong links between metabolism, cellular differentiation, and virulence of L. pneumophila. Herein, we focus on current knowledge of the metabolic components employed by intracellular L. pneumophila for cell differentiation, nutrient salvaging and utilization of host factors. Specifically, we highlight the metabolic cues that are coupled to bacterial differentiation, nutrient acquisition systems, and the strategies utilized by L. pneumophila to exploit host metabolites for intracellular replication. [ABSTRACT FROM AUTHOR]

Reports on the structure of adenosine triphosphate (ATP):corrinoid adenosyltransferase from Salmonella typhimurium in its substrate-free state, complexed with MgATP or with hydroxocobalamin and MgATP. Formation of the cobalt-carbon bond; MgATP and hydroxocobalamin binding sites; Interactions between the protein and polar side chains of corrin ring.