Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0038187 (starvation)
 24,951 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A 41-kDa protein of Nitrosomonas eutropha was purified, and the N-terminal amino acid sequence was found to be nearly identical with the sequence of AmoB, a subunit of ammonia monooxygenase. This protein was used to develop polyclonal antibodies, which were highly specific for the detection of the four genera of ammonia oxidizers of the beta-subclass of Proteobacteria (Nitrosomonas, including Nitrosococcus mobilis, which belongs phylogenetically to Nitrosomonas; Nitrosospira; Nitrosolobus; and Nitrosovibrio). In contrast, the antibodies did not react with ammonia oxidizers affiliated with the gamma-subclass of Proteobacteria (Nitrosococcus oceani and Nitrosococcus halophilus). Moreover, methane oxidizers (Methylococcus capsulatus, Methylocystis parvus, and Methylomonas methanica) containing the related particulate methane monooxygenase were not detected. Quantitative immunoblot analysis revealed that total cell protein of N. eutropha consisted of approximately 6% AmoB, when cells were grown using standard conditions (mineral medium containing 10 mM ammonium). This AmoB amount was shown to depend on the ammonium concentration in the medium. About 14% AmoB of total protein was found when N. eutropha was grown with 1 mM ammonium, whereas 4% AmoB was detected when 100 mM ammonium were used. In addition, the cellular amount of AmoB was influenced by the absence of the substrate. Cells starved for more than 2 months contained nearly twice as much AmoB as actively growing cells, although these cells possessed low ammonia-oxidizing activity. AmoB was always present and could even be detected in cells of Nitrosomonas after 1 year of ammonia starvation.
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PMID:Polyclonal antibodies recognizing the AmoB protein of ammonia oxidizers of the beta-subclass of the class Proteobacteria. 1113 35

Methanobactins (Mbns) are ribosomally produced, post-translationally modified peptide (RiPP) natural products that bind copper with high affinity using nitrogen-containing heterocycles and thioamide groups. In some methanotrophic bacteria, Mbns are secreted under conditions of copper starvation and then re-internalized as a copper source for the enzyme particulate methane monooxygenase (pMMO). Genome mining studies have led to the identification and classification of operons encoding the Mbn precursor peptide (MbnA) as well as a number of putative transport, regulatory, and biosynthetic proteins. These Mbn operons are present in non-methanotrophic bacteria as well, suggesting a broader role in and perhaps beyond copper acquisition. Genetic and biochemical studies indicate that specific operon-encoded proteins are involved in Mbn transport and provide insight into copper-responsive gene regulation in methanotrophs. Mbn biosynthesis is not yet understood, but combined analysis of Mbn structures, MbnA sequences, and operon content represents a powerful approach to elucidating the roles of specific biosynthetic enzymes. Future work will likely lead to the discovery of unique pathways for natural product biosynthesis and new mechanisms of microbial metal homeostasis.
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PMID:Methanobactins: from genome to function. 2790 14