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Poirel L,
Héritier C,
Nordmann P,
( 2004 ) Chromosome-encoded ambler class D beta-lactamase of Shewanella oneidensis as a progenitor of carbapenem-hydrolyzing oxacillinase. PMID : 14693565 : DOI : 10.1128/aac.48.1.348-351.2004 PMC : PMC310178 Abstract >>
A chromosome-encoded beta-lactamase gene from a Shewanella oneidensis reference strain was cloned and expressed in Escherichia coli. It encoded a carbapenem-hydrolyzing Ambler class D beta-lactamase, OXA-54, that shared 92% amino acid identity with the plasmid-encoded carbapenem-hydrolyzing oxacillinase OXA-48 from Klebsiella pneumoniae. This work suggests that Shewanella spp. may produce the progenitor of oxacillinases compromising the efficacy of imipenem in clinically relevant gram-negative pathogens.
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Ceccarelli D,
van Essen-Zandbergen A,
Veldman KT,
Tafro N,
Haenen O,
Mevius DJ,
( 2017 ) Chromosome-Based blaOXA-48-Like Variants in Shewanella Species Isolates from Food-Producing Animals, Fish, and the Aquatic Environment. PMID : 27855066 : DOI : 10.1128/AAC.01013-16 PMC : PMC5278689 Abstract >>
Carbapenems are considered last-resort antibiotics in health care. Increasing reports of carbapenemase-producing bacteria in food-producing animals and in the environment indicate the importance of this phenomenon in public health. Surveillance for carbapenemase genes and carbapenemase-producing bacteria in Dutch food-producing animals, environmental freshwater, and imported ornamental fish revealed several chromosome-based blaOXA-48-like variants in Shewanella spp., including two new alleles, blaOXA-514 and blaOXA-515 Carbapenemase genes were not associated with mobile genetic elements or Enterobacteriaceae.
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3. |
Kuchenreuther JM,
George SJ,
Grady-Smith CS,
Cramer SP,
Swartz JR,
( 2011 ) Cell-free H-cluster synthesis and [FeFe] hydrogenase activation: all five CO and CN? ligands derive from tyrosine. PMID : 21673792 : DOI : 10.1371/journal.pone.0020346 PMC : PMC3105041 Abstract >>
[FeFe] hydrogenases are promising catalysts for producing hydrogen as a sustainable fuel and chemical feedstock, and they also serve as paradigms for biomimetic hydrogen-evolving compounds. Hydrogen formation is catalyzed by the H-cluster, a unique iron-based cofactor requiring three carbon monoxide (CO) and two cyanide (CN?) ligands as well as a dithiolate bridge. Three accessory proteins (HydE, HydF, and HydG) are presumably responsible for assembling and installing the H-cluster, yet their precise roles and the biosynthetic pathway have yet to be fully defined. In this report, we describe effective cell-free methods for investigating H-cluster synthesis and [FeFe] hydrogenase activation. Combining isotopic labeling with FTIR spectroscopy, we conclusively show that each of the CO and CN? ligands derive respectively from the carboxylate and amino substituents of tyrosine. Such in vitro systems with reconstituted pathways comprise a versatile approach for studying biosynthetic mechanisms, and this work marks a significant step towards an understanding of both the protein-protein interactions and complex reactions required for H-cluster assembly and hydrogenase maturation.
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