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Structures, reactivities, and antibiotic properties of the marinopyrroles A-F.

ABSTRACT: Cultivation of actinomycete strain CNQ-418, retrieved from a deep ocean sediment sample off the coast of La Jolla, CA, has provided marinopyrroles A-F. Sharing just 98% 16S rRNA gene sequence identity with S. sannurensis, the strain likely represents a new Streptomyces species. The metabolites contain an unusual 1,3'-bipyrrole core decorated with several chlorine and bromine substituents and possess marked antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA). The congested N,C-biaryl bond establishes an axis of chirality that, for marinopyrroles A-E, is configurationally stable at room temperature. Moreover, the natural products are fashioned strictly in the M-configuration. The Paal-Knorr condensation was adapted for the synthesis of the 1,3'-bipyrrole core. Halogenation of this material with N-bromosuccinimide cleanly furnished the 4,4',5,5'-tetrahalogenated core that characterizes this class of marine-derived metabolites.

SUBMITTER: Hughes CC

PROVIDER: S-EPMC2884375 | biostudies-literature | 2010 May

REPOSITORIES: biostudies-literature

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Structures, reactivities, and antibiotic properties of the marinopyrroles A-F.

Hughes Chambers C CC Kauffman Christopher A CA Jensen Paul R PR Fenical William W

The Journal of organic chemistry 20100501 10

Cultivation of actinomycete strain CNQ-418, retrieved from a deep ocean sediment sample off the coast of La Jolla, CA, has provided marinopyrroles A-F. Sharing just 98% 16S rRNA gene sequence identity with S. sannurensis, the strain likely represents a new Streptomyces species. The metabolites contain an unusual 1,3'-bipyrrole core decorated with several chlorine and bromine substituents and possess marked antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA). The con ...[more]

PMID: 20405892

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Project description:Mononuclear non-heme iron complexes that serve as structural and functional mimics of the thiol dioxygenases (TDOs), cysteine dioxygenase (CDO) and cysteamine dioxygenase (ADO), have been prepared and characterized with crystallographic, spectroscopic, kinetic, and computational methods. The high-spin Fe(II) complexes feature the facially coordinating tris(4,5-diphenyl-1-methylimidazol-2-yl)phosphine (Ph2TIP) ligand that replicates the three histidine (3His) triad of the TDO active sites. Further coordination with bidentate l-cysteine ethyl ester (CysOEt) or cysteamine (CysAm) anions yielded five-coordinate (5C) complexes that resemble the substrate-bound forms of CDO and ADO, respectively. Detailed electronic-structure descriptions of the [Fe(Ph2TIP)(LS,N)]BPh4 complexes, where LS,N = CysOEt (1) or CysAm (2), were generated through a combination of spectroscopic techniques [electronic absorption, magnetic circular dichroism (MCD)] and density functional theory (DFT). Complexes 1 and 2 decompose in the presence of O2 to yield the corresponding sulfinic acid (RSO2H) products, thereby emulating the reactivity of the TDO enzymes and related complexes. Rate constants and activation parameters for the dioxygenation reactions were measured and interpreted with the aid of DFT calculations for O2-bound intermediates. Treatment of the TDO models with nitric oxide (NO)-a well-established surrogate of O2-led to a mixture of high-spin and low-spin {FeNO}7 species at low temperature (-70 °C), as indicated by electron paramagnetic resonance (EPR) spectroscopy. At room temperature, these Fe/NO adducts convert to a common species with EPR and infrared (IR) features typical of cationic dinitrosyl iron complexes (DNICs). To complement these results, parallel spectroscopic, computational, and O2/NO reactivity studies were carried out using previously reported TDO models that feature an anionic hydrotris(3-phenyl-5-methyl-pyrazolyl)borate (Ph,MeTp-) ligand. Though the O2 reactivities of the Ph2TIP- and Ph,MeTp-based complexes are quite similar, the supporting ligand perturbs the energies of Fe 3d-based molecular orbitals and modulates Fe-S bond covalency, suggesting possible rationales for the presence of neutral 3His coordination in CDO and ADO.

Project description:Single and multiple layers of sub-wavelength periodic Babinet complementary patterns composed of rounded nano-object miniarrays were investigated. In case of illumination with linearly and circularly polarized light the azimuthal orientation and handedness (in)dependence of (cross-polarized) copolarized transmitted signal components was proven for all types of patterns. Considerable (weak) asymmetric transmission was demonstrated in extended bands exclusively for both types of copolarized (cross-polarized) signals transmitted through single layer of convex miniarrays. Three-dimensional structures constructed with convex-concave-convex complex pattern-layers resulted in a negative index at the visible region boundary both for linearly and circularly polarized light illuminations. This is because dipolar modes on the convex nano-objects are synchronized with co-existent reversal dipoles on the concave nano-objects via interlayer coupling. Although during linearly polarized light illumination, the interlayer interaction decouples the localized and propagating modes excitable on the concave pattern in the 90° azimuthal orientation, the synchronization via tilted-rotating nanoring dipoles is almost perfect in the 0° azimuthal orientation. For circularly polarized light illumination, both the dispersion maps and the negative index phenomena synthesize the characteristics of the two orthogonal linearly polarized light illuminations. Important aspect is the appearance of a small/intermediate (large) time-averaged amplitude magnetic dipole due to the tilted (twisted) electric dipole on the concave nanoring, which less/more quickly turns (continuously rotates) with large/intermediate (small) out-of-plane tilting, when illumination is realized with linearly polarized light in the 90°/0° azimuthal orientation (with circularly polarized light). The location of the negative index can be predicted based on the copolarized transmittance signals computed for circularly polarized light illumination by using the linear base representation of Jones transmission matrix elements.

Dataset Information

Structures, reactivities, and antibiotic properties of the marinopyrroles A-F.

Publications

Structures, reactivities, and antibiotic properties of the marinopyrroles A-F.

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