Megan L Matthews

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To test its phylogenetic utility, nucleotide sequence variation in a 1,240-bp fragment of the elongation factor-1 alpha (EF-1 alpha) gene was examined in 49 moth species representing the major groups of the superfamily Noctuoidea. Both parsimony and distance analyses supported the monophyly of nearly all groups for which there are clear morphological(More)
The allelic identities of Single Nucleotide Repeat (SNR) markers in Bacillus anthracis are typically ascertained by DNA sequencing through the direct repeat. Here we describe a reproducible method for genotyping closely related isolates by using four SNR loci in a multiplex-PCR capillary electrophoresis system amenable to high-throughput analysis.
The lack of a readily accessible roster of nuclear genes informative at various taxonomic levels is a bottleneck for molecular systematics. In this report, we describe the first phylogenetic application of the sequence that encodes the enzyme dopa decarboxylase (DDC). For 14 test species within the noctuid moth subfamily Heliothinae that represent the(More)
The gene cluster from Pantoea agglomerans responsible for biosynthesis of the dapdiamide antibiotics encodes an adenylation-thiolation didomain protein, DdaD, and an Fe(II)/α-ketoglutarate-dependent dioxygenase homologue, DdaC. Here we show that DdaD, a nonribosomal peptide synthetase module, activates and sequesters N(β)-fumaramoyl-l-2,3-diaminopropionate(More)
Mononuclear non-haem iron (NHFe) enzymes catalyse a broad range of oxidative reactions, including halogenation, hydroxylation, ring closure, desaturation and aromatic ring cleavage reactions. They are involved in a number of biological processes, including phenylalanine metabolism, the production of neurotransmitters, the hypoxic response and the(More)
Aliphatic halogenases activate O(2), cleave alpha-ketoglutarate (alphaKG) to CO(2) and succinate, and form haloferryl [X-Fe(IV)O; X = Cl or Br] complexes that cleave aliphatic C-H bonds to install halogens during the biosynthesis of natural products by non-ribosomal peptide synthetases (NRPSs). For the related alphaKG-dependent dioxygenases, it has been(More)
The alpha-ketoglutarate-dependent hydroxylases and halogenases employ similar reaction mechanisms involving hydrogen-abstracting Fe(IV)-oxo (ferryl) intermediates. In the halogenases, the carboxylate residue from the His(2)(Asp/Glu)(1) "facial triad" of iron ligands found in the hydroxylases is replaced by alanine, and a halide ion (X(-)) coordinates at the(More)
A challenge in the computational design of enzymes is that multiple properties, including substrate binding, transition state stabilization and product release, must be simultaneously optimized, and this has limited the absolute activity of successful designs. Here, we focus on a single critical property of many enzymes: the nucleophilicity of an active(More)
Iron-dependent halogenases employ cis-halo-Fe(IV)-oxo (haloferryl) complexes to functionalize unactivated aliphatic carbon centers, a capability elusive to synthetic chemists. Halogenation requires (i) coordination of a halide anion (Cl(-) or Br(-)) to the enzyme's Fe(II) cofactor, (ii) coupled activation of O2 and decarboxylation of α-ketoglutarate to(More)