X-Ray molecular structure of caissarone, a novel purine derivative from the sea anemone Bunodosoma caissarum Correa 1964

Zelnik, R.; Haraguchi, Mitsue; Matida, Amabile K.; Lavie, David; Frolow, Felix; Weis, Alexander L.

doi:10.1039/p19860002051

Cited by 27 publications

(17 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Accordingly, as mentioned above, 1 and 2 are investigated to provide information on the structure of the photoisomerization path of contact ion pairs. The Cl (Ϫ) counterion (that results from the Schiff base protonation with HCl) is placed along the N-H axis as suggested by NMR simulations (38,39) and to mimic the hydrogen bond of crystal structures of related compounds (40)(41)(42)(43). Most importantly, to relate the behavior of the isolated ion pair with the behavior in solution, the NOCl distance is fixed at 5.25 Å.…”

mentioning

confidence: 99%

The retinal chromophore/chloride ion pair: Structure of the photoisomerization path and interplay of charge transfer and covalent states

Cembran

Bernardi

Olivucci

et al. 2005

Proc. Natl. Acad. Sci. U.S.A.

113

109

View full text Add to dashboard Cite

Ab initio multireference second-order perturbation theory computations are used to explore the photochemical behavior of two ion pairs constituted by a chloride counterion interacting with either a rhodopsin or bacteriorhodopsin chromophore model (i.e., the 4-cis-␥-methylnona-2,4,6,8-tetraeniminium and all-trans-nona-2,4,6,8-tetraeniminium cations, respectively). Significant counterion effects on the structure of the photoisomerization paths are unveiled by comparison with the paths of the same chromophores in vacuo. Indeed, we demonstrate that the counterion (i) modulates the relative stability of the S0, S1, and S2 energy surfaces leading to an S1 isomerization energy profile where the S1 and S2 states are substantially degenerate; (ii) leads to the emergence of significant S 1 energy barriers along all of the isomerization paths except the one mimicking the 11-cis 3 all-trans isomerization of the rhodopsin chromophore model; and (iii) changes the nature of the S1 3 S0 decay funnel that becomes a stable excited state minimum when the isomerizing double bond is located at the center of the chromophore moiety. We show that these (apparently very different) counterion effects can be rationalized on the basis of a simple qualitative electrostatic model, which also provides a crude basis for understanding the behavior of retinal protonated Schiff bases in solution.ab initio ͉ counterion ͉ conical intersection ͉ protonated Schiff base R etinal proteins (1-4) include the retina visual pigment rhodopsin (Rh) and the bacterial proton-pump bacteriorhodopsin (bR). The biological activity of these pigments is triggered by the ultrafast light-induced cis-trans isomerization of their chromophores. These correspond to the 11-cis (PSB11) and all-trans (PSBT) stereoisomers of the protonated Schiff base (PSB) of retinal respectively. Recently, we have reported (5-7) the computed photoisomerization path of different models of PSB11 and PSBT in vacuo. It has been shown that, invariably, the excited state branch of the path develops entirely along a charge transfer state (that can be related to the 1B u , i.e., hole pair, state of polyenes) that corresponds to the first singlet excited state (S 1 ) of the system and ends at a peaked conical intersection (CI) where the S 1 and ground (S 0 ) state energy surfaces cross. Because the CI features an Ϸ90°t wisted double bond, its geometrical and electronic structure is consistent with that of a twisted intramolecular charge transfer (TICT) state (5-7). The corresponding S 1 isomerization coordinate, starting at a planar Franck-Condon (FC) point, is bimodal being sequentially dominated by two uncoupled modes. The first corresponds to a stretching mode involving C-C bonds order inversion. The second mode breaks the planar symmetry and is dominated by a one-bond-flip (OBF) (8, 9) twisting of the reacting double bond.In Fig. 1, we report the computed energy profiles and give a pictorial view of the structure of the S 1 energy surface of the PSB11 model 4-cis-␥-methylnona-2,4,6,8-tetraenimin...

show abstract

mentioning

confidence: 99%

The retinal chromophore/chloride ion pair: Structure of the photoisomerization path and interplay of charge transfer and covalent states

Cembran

Bernardi

Olivucci

et al. 2005

Proc. Natl. Acad. Sci. U.S.A.

113

109

View full text Add to dashboard Cite

show abstract

“…On the other hand, non-proteinaceous compounds have been found, such as purines, quaternary ammonium compounds, biogenic amines and betaines [57][58][59] but these are much smaller, less charged and less hydrophobic than peptides and proteins so they can be easily distinguished and separated in early purification steps.…”

Section: Discussionmentioning

confidence: 98%

Combining multidimensional liquid chromatography and MALDI–TOF-MS for the fingerprint analysis of secreted peptides from the unexplored sea anemone species Phymanthus crucifer

Rodríguez

Ständker

Zaharenko

et al. 2012

Journal of Chromatography B

View full text Add to dashboard Cite

“…The first instance of an aturally occurring 8-oxoAde derivativec orresponds to an N1-,N 9-methylated, 6imino purine ring described as a"new marine purine characterized by the rare in nature 8-oxo function". [68] Caissarone has been stud- ied for its effects on the development of fertilized eggs of the sea-urchin Lytechinus variegatus [69] as well as for its pharmacological activity as an adenosine receptor antagonist. [66] Interestingly,a nd as described in Section 2.1, the keto-derivative is the predominant tautomer with aC =Ob ond length of 1.23 .T he total synthesis for this purine derivative was achieved with two routes that start with C8-brominated N9-Me adenine.…”

Section: Naturalproduct Derivativesmentioning

confidence: 99%

“…[67] Another alkylated derivative is Caissarone, which is an N3-, N6-, N9-methylated compound that was isolated and characterizedv ia X-ray crystallography. [68] Caissarone has been stud- Chem. Eur.J.…”

Section: Naturalproduct Derivativesmentioning

confidence: 99%

8‐Oxo‐7,8‐dihydroadenine and 8‐Oxo‐7,8‐dihydroadenosine—Chemistry, Structure, and Function in RNA and Their Presence in Natural Products and Potential Drug Derivatives

Choi

Chang

Gibala

et al. 2017

Chemistry A European J

View full text Add to dashboard Cite

A description and history of the role that 8-oxo-7,8-dihydroadenine (8-oxoAde) and 8-oxo-7,8-dihydroadenosine (8-oxoA) have in various fields has been compiled. This Review focusses on 1) the formation of this oxidatively generated modification in RNA, its interactions with other biopolymers, and its potential role in the development/progression of disease; 2) the independent synthesis and incorporation of this modified nucleoside into oligonucleotides of RNA to display the progress that has been made in establishing its behavior in biologically relevant systems; 3) reported synthetic routes, which date back to 1890, along with the progress that has been made in the total synthesis of the nucleobase, nucleoside, and their corresponding derivatives; and 4) the isolation, total synthesis, and biological activity of natural products containing these moieties as the backbone. The current state of research regarding this oxidatively generated lesion as well as its importance in the context of RNA, natural products, and potential as drug derivatives is illustrated using all available examples reported to date.

show abstract

X-Ray molecular structure of caissarone, a novel purine derivative from the sea anemone Bunodosoma caissarum Correa 1964

Cited by 27 publications

References 0 publications

The retinal chromophore/chloride ion pair: Structure of the photoisomerization path and interplay of charge transfer and covalent states

The retinal chromophore/chloride ion pair: Structure of the photoisomerization path and interplay of charge transfer and covalent states

Combining multidimensional liquid chromatography and MALDI–TOF-MS for the fingerprint analysis of secreted peptides from the unexplored sea anemone species Phymanthus crucifer

8‐Oxo‐7,8‐dihydroadenine and 8‐Oxo‐7,8‐dihydroadenosine—Chemistry, Structure, and Function in RNA and Their Presence in Natural Products and Potential Drug Derivatives

Contact Info

Product

Resources

About