Complementarity and chiral recognition: enantioselective complexation of bilirubin

Lightner, David A.; Gawroński, Jacek; Wijekoon, W. M. D.

doi:10.1021/ja00255a020

Cited by 130 publications

(74 citation statements)

References 2 publications

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“…Computational analyses 8,12 confirmed by experiment, 9,[15][16][17][18][19] indicate that the M-helical conformer ( Fig. 1) will exhibit a negative exciton chirality (long wavelength negative, short wavelength positive) for the CD couplet corresponding to the pigment's long wavelength absorption band(s) near 400 nm and the P-helical conformation is predicted to exhibit a positive exciton CD couplet (long wavelength positive, short wavelength negative).…”

Section: Chirality Inversionmentioning

confidence: 91%

“…1) and correlations between pigment propeller stereochemistry (M and P) and CD spectroscopy have been drawn on the basis of exciton coupling theory. 8,9,12,18,22 …”

Section: Exciton Chiralitymentioning

confidence: 99%

“…4) and the predictions of the exciton chirality rule. 8,9,12,18,19,22 Curiously, when ammonia gas is added to a solution of 1 in CHCl 3 the Cotton effect magnitudes decrease with increasing NH 3 concentration. At sufficiently high concentration the Cotton effect signs invert and the intensity grows, reaching a plateau where the magnitudes are comparable to or greater than those of 1 in pure CHCl 3 .…”

Section: Chirality Inversionmentioning

confidence: 99%

“…1, lower). Displacement of the equilibrium toward the M or P can be achieved by enantioselective complexation with a chiral compound such as quinine, 12 serum albumin, 13,14 or by the action of intramolecular nonbonded steric repulsions, as has been observed when stereogenic centers are created by methyl substitution at either the ␣ or the ␤ carbons of the propionic acid chains. 9,15 It is this latter phenomenon that has attracted our interest because such "intramolecular resolution" can be observed by circular dichroism spectroscopy.…”

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confidence: 99%

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Chirality inversion in the bilirubin molecular exciton

Boiadjiev

Lightner

2001

Chirality

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The bichromophoric pigment bilirubin acts as a molecular exciton in its UV-visible and circular dichroism (CD) spectroscopy. In both polar and nonpolar solvents, an optically active analog, (beta R,beta 'R)-dimethylmesobilirubin-XIII alpha (1), exhibits intense bisignate CD Cotton effects in the region of its long wavelength UV-vis absorption near 400 nm: Delta epsilon(434)(max) + 337, Delta epsilon(389)(max) - 186 (CHCl(3)), and Delta epsilon(431)(max) + 285, Delta epsilon(386)(max) - 177 (CH(3)OH). However, introduction of an amine into a CHCl(3) solution of 1 causes the Cotton effect signs to become inverted, e.g., after addition of NH(3), Delta epsilon(433)(max) - 345, Delta epsilon(389)(max) + 243, and after addition of ethylene diamine, Delta epsilon(435)(max) - 420, Delta epsilon(390)(max) + 299. The sign inversions imply inversion of molecular chirality of the bilirubin and the phenomenon appears to be general for amines, including alpha,omega-diamines. 1,8-Diaminooctane was found to be more effective than longer or shorter chain analogs in producing CD sign inversion.

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Section: Chirality Inversionmentioning

confidence: 91%

“…1) and correlations between pigment propeller stereochemistry (M and P) and CD spectroscopy have been drawn on the basis of exciton coupling theory. 8,9,12,18,22 …”

Section: Exciton Chiralitymentioning

confidence: 99%

Section: Chirality Inversionmentioning

confidence: 99%

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confidence: 99%

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Chirality inversion in the bilirubin molecular exciton

Boiadjiev

Lightner

2001

Chirality

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“…On the other hand, their main function in photosynthesis appears to not involve "chirality" and their spatial arrangement-more so than that of hemes-is often characterized by a high degree of symmetry. This intriguing dichotomy and our longstanding interest in structure-function relationships in photosynthetic pigments prompted the present attempt to take an initial look at aspects of chirality and symmetry of chlorophylls in photosynthesis to stimulate further interest in this area of research [27] (and [28][29][30]). …”

Section: Scope Of the Reviewmentioning

confidence: 99%

Chlorophylls, Symmetry, Chirality, and Photosynthesis

et al. 2014

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Chlorophylls are a fundamental class of tetrapyrroles and function as the central reaction center, accessory and photoprotective pigments in photosynthesis. Their unique individual photochemical properties are a consequence of the tetrapyrrole macrocycle, the structural chemistry and coordination behavior of the phytochlorin system, and specific substituent pattern. They achieve their full potential in solar energy conversion by working in concert in highly complex, supramolecular structures such as the reaction centers and light-harvesting complexes of photobiology. The biochemical function of these structures depends on the controlled interplay of structural and functional principles of the apoprotein and pigment cofactors. Chlorophylls and bacteriochlorophylls are optically active molecules with several chiral centers, which are necessary for their natural biological function and the assembly of their supramolecular complexes. However, in many cases the exact role of chromophore stereochemistry in the biological context is unknown. This review gives an overview of chlorophyll research in terms of basic function, biosynthesis and their functional and structural role in photosynthesis. It highlights aspects of chirality and symmetry of chlorophylls to elicit further interest in their role in nature.

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Exciton chirality of bilirubin homologs

Boiadjiev

Lightner

1997

Chirality

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Bilirubin, the yellow pigment of jaundice, is a bichromophoric tetrapyrrole that readily adopts either of two enantiomeric, folded conformations shaped like ridge‐tiles and stabilized by a network of six intramolecular hydrogen bonds. Interconversion of these M and P helical chirality conformational enantiomers is rapid at room temperature but may be displaced toward either enantiomer by intramolecular nonbonded steric interactions. Introduction of a methyl group at the β and β′ carbons of the propionic acid chains on the symmetric bilirubin analog, mesobilirubin‐XIIIα, shifts the conformational equilibrium toward the M or the P‐chirality intramolecularly hydrogen‐bonded conformer, depending only on the S or R stereochemistry at β and β′, resulting in pigments with intense exciton coupling circular dichroism (CD) for the ∼430 nm transition(s). Optically active synthetic analogs of bilirubin with propionic acid groups lengthened systematically to heptanoic acid (1–5) were synthesized and examined by spectroscopy to explore the influence of alkanoic acid chain length on conformation and intramolecular hydrogen bonding. In these diacids and their dimethyl esters (6–10), strong exciton chirality CD spectra are observed, and the data are correlated with molecular helicity. Chirality 9:604–615, 1997. © 1997 Wiley‐Liss, Inc.

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Complementarity and chiral recognition: enantioselective complexation of bilirubin

Cited by 130 publications

References 2 publications

Chirality inversion in the bilirubin molecular exciton

Chirality inversion in the bilirubin molecular exciton

Chlorophylls, Symmetry, Chirality, and Photosynthesis

Exciton chirality of bilirubin homologs

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