The Stereostructure of Porphyra‐334: An Experimental and Calculational NMR Investigation. Evidence for an Efficient ‘Proton Sponge’

Klisch, Manfred; Richter, Peter; Puchta, Ralph; Häder, Donat‐P.; Bauer, Walter

doi:10.1002/hlca.200790052

Cited by 46 publications

(49 citation statements)

References 59 publications

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“…The positive charge on a nitrogen atom is delocalized over the chromophore by conjugation (Figure 3). According to DFT calculations by Klisch et al , it was found that the NMR chemical shift assignable to imine carbon of porphyra-334 agreed strongly with the calculation result, which was obtained using a protonated form of porphyra-334 [49]. This calculation result also supports that the configuration at the imine site is estimated as predominantly ( E , E ) form.…”

Section: Sunscreen Pigmentssupporting

confidence: 74%

Multiple Roles of Photosynthetic and Sunscreen Pigments in Cyanobacteria Focusing on the Oxidative Stress

2013

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Cyanobacteria have two types of sunscreen pigments, scytonemin and mycosporine-like amino acids (MAAs). These secondary metabolites are thought to play multiple roles against several environmental stresses such as UV radiation and desiccation. Not only the large molar absorption coefficients of these sunscreen pigments, but also their antioxidative properties may be necessary for the protection of biological molecules against the oxidative damages induced by UV radiation. The antioxidant activity and vitrification property of these pigments are thought to be requisite for the desiccation and rehydration processes in anhydrobiotes. In this review, the multiple roles of photosynthetic pigments and sunscreen pigments on stress resistance, especially from the viewpoint of their structures, biosynthetic pathway, and in vitro studies of their antioxidant activity, will be discussed.

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Section: Sunscreen Pigmentssupporting

confidence: 74%

Multiple Roles of Photosynthetic and Sunscreen Pigments in Cyanobacteria Focusing on the Oxidative Stress

2013

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“…HMQC and HMBC experiments revealed the following (see the Table) HMBC Correlation from CH 2 (11) (d 3.40) to C(3) located the 2-hydroxyethyl group at the iminic N-atom connected to C(3) to establish planar structure of 1. The configuration of the cyclohexane ring at C(5) was reported in [10]. The configuration at C(12) was not determined.…”

mentioning

confidence: 91%

“…1). Compounds 1 -3 are structurally related to 5, an imino-MAA, and 1 is the decarboxylated analog of porphyra-334, which has been known for three decades [10]. Compound 1 is N-isopropanolpalythine (¼ aplysiapalythine A (APA)), 2 is N-ethylpalythine (¼ aplysiapalythine B (APB)), and 3 is N-methylpalythine (¼ aplysiapalythine C (APC)).…”

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confidence: 99%

Isolation and Structural Elucidation of Novel Mycosporine‐Like Amino Acids as Alarm Cues in the Defensive Ink Secretion of the Sea Hare Aplysia californica

Kamio

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Nguyen

et al. 2011

Helvetica Chimica Acta

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Three new mycosporine-like amino acids (MAAs), aplysiapalythines A, B, and C (1, 2, and 3, resp.) were isolated from opaline, a glandular component of the defensive ink secretion of sea hares (Aplysia californica) collected from waters off southern California. Here, we report the structure of these MAAs determined by mass spectrometry and NMR data. These new MAAs are structurally related to two known MAAs that are also present in sea hare opaline, i.e., asterina 330 (4) and palythine (5), and for which we also provide detailed data here for comparison. The fact that three of the five MAAs that we identified from sea hare opaline are novel molecules is interesting given that this represents a relatively large addition to the current list of known MAAs. This is likely because most researchers have identified MAAs through HPLC with UV detection, which is imprecise given similarities in UV spectra for different MAAs. Our findings suggest that there is much greater diversity of MAAs than is currently known. Results published elsewhere show that 1, 2, and 4 are alarm cues for conspecific sea hares at natural concentrations, but 3 and 5 are not.Introduction. -Mycosporine-like amino acids (MAAs) are widely distributed in marine organisms including bacteria, plants, invertebrates, and vertebrates [1]. Animals are generally thought to be incapable of synthesizing MAAs, but rather they are thought to sequester MAAs from their diet or from symbionts; however, this view has been questioned [2]. MAAs, of which ca. 30 are known, are traditionally considered to be screens against solar radiation, but other functions have also been proposed, including anti-oxidants, osmotic regulation, providing a source of amino acids in embryonic development, and induction of spawning [3 -10].A new function for MAAs was recently identified from our work on chemical defenses of sea hares (Aplysia californica) collected from the waters of southern California [11]. We found that MAAs are present in high concentrations in opaline, which is one of the glandular products of the sea hares ink secretion. Of the five major MAAs in opaline of these sea hares, three are novel, and two of these novel MAAs, together with nucleic acids and nucleosides in the ink component of the sea hares ink secretion, function as intraspecific alarm cues [11]. In this article, we describe the isolation and the structure elucidation of these novel MAAs.

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“…P-334 can be called a “proton sponge compound [11]”, because it can form strong intramolecular interactions. At pD 1.0, the cycles of the electronic orbitals were C (8) H 3 –O…H–N–C (1) …C (2) and C (8) H 3 –O…H–N–C (3) …C (2) (Figure 3a).…”

Section: Resultsmentioning

confidence: 99%

Porphyra-334 Isolated from the Marine Algae Bangia atropurpurea: Conformational Performance for Energy Conversion

2014

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Prophyra-334 (p-334) may play a role of energy transfer under an uncertain mechanism, and we speculate the possible model. Via 1D and 2D NMR experiments, it was simulated the correlation between dissociation and conformation of p-334. Intramolecular interactions were observed based on a series of changes in the 1H and 13C chemical shifts. Nuclear Overhauser effect spectroscopy experiments and molecular models in various pD conditions indicated the p-334 molecular dissociation process status. In addition, we also used Chem3D software to find the most possible molecular conformation. The relationship between the structural status and energy conversion is explained. Those are the primary results. More researches on it are highly expected in the future.

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The Stereostructure of Porphyra‐334: An Experimental and Calculational NMR Investigation. Evidence for an Efficient ‘Proton Sponge’

Cited by 46 publications

References 59 publications

Multiple Roles of Photosynthetic and Sunscreen Pigments in Cyanobacteria Focusing on the Oxidative Stress

Multiple Roles of Photosynthetic and Sunscreen Pigments in Cyanobacteria Focusing on the Oxidative Stress

Isolation and Structural Elucidation of Novel Mycosporine‐Like Amino Acids as Alarm Cues in the Defensive Ink Secretion of the Sea Hare Aplysia californica

Porphyra-334 Isolated from the Marine Algae Bangia atropurpurea: Conformational Performance for Energy Conversion

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