Resonance Raman and infrared studies on axial coordination to chlorophylls a and b in vitro

Fujiwara, Mai; Tasumi, Mitsuo

doi:10.1021/j100274a009

Cited by 137 publications

(131 citation statements)

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“…Similar relationships are observed between spectral shifts of ir bands and the following structural parameters: (a) the strength of the N-metal bond (13,14); (b) the number of d electrons on the metal (16); (c) the center-to-nitrogen distance or core size (7,35,(39)(40)(41); (d) the stability of the complexes (38); (e) the spectral shifts in the UV-vis region (7,12,42). The correlation factors between the ir displacement and the parameters mentioned are seldom greater than 0.9 even when the series of complexes are restricted to the ones formed with the elements of one single group or with the elements of a period in the periodic table.…”

Section: Far-infrared Regionsupporting

confidence: 59%

Vibrational and electronic spectra of new liposoluble metalloporphyrins in a nonpolar noncoordinating solvent

Ringuet¹,

Girard²,

Chapados³

1991

Can. J. Chem.

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MICHEL RINGUET, DENIS GIRARD, and CAMILLE CHAPADOS. Can. J. Chem. 69, 1070 (1991). A new liposoluble porphyrin, 2,7,12,17-tetrahexyl-3,8,13,18-tetramethylporphin (THTMP), and its complexes with divalent (Mg, Co, Ni, Cu, Zn, Cd, Hg) and trivalent (Mn, Fe) metals have been synthesized. The electronic, infrared, and far-infrared spectra of these compounds were obtained in the same nonpolar, noncoordinating solvent, CC14. After comparison with the experimental data and the results of normal coordinate analyses from the literature, the assignment of the vibrational bands of THTMP and its complexes is made. Some correlations between the shifts of the metal sensitive bands in the diffferent regions and the structural characteristics of the porphyrin complexes are reported. Some emphasis is made on the magnesium complex in relation to chlorophyll.Key words: Metalloporphyrin, porphyrin, infrared spectroscopy, far-infrared spectroscopy, electronic spectroscopy, nitrogen-metal bond, covalent radius, reduced mass.MICHEL RINGUET, DENIS GIRARD et CAMILLE CHAPADOS. Can. J. Chem. 69, 1070 (1991). On prisente la synthkse d'une nouvelle porphyrine liposoluble, la tetrahexyl-2,7,12,17 tetramtthyl-3,8,13,18 porphine (THTMP), et de ses complexes de mttaux bivalents (Mg, Co, Ni, Cu, Zn, Cd, Hg) et trivalents (Mn, Fe). On aobtenu les spectres Clectroniques, dans l'infrarouge et dans l'infrarouge lointain, de ces substances en solution dans un mCme solvant non polaire et non coordonnant, le CCl,. Les bandes vibrationnelles sont attribuees 21 la suite de comparaisons avec les spectres et les rtsultats d'analyses de coordonnees normales dejh publies. On ktablit des corrklations entre les dtplacements des bandes influenckes par le metal dans les differentes regions spectrales et diverses caractkristiques physicochimiques des mktalloporphyrines. On porte une attention particulitre aux spectres de la porphyrine de magnesium en regard des spectres de la chlorophylle.Mots cle's : mktalloporphyrine, porphyrine, spectroscopie infrarouge, spectroscopie dans l'infrarouge lointain, spectroscopie klectronique, liaison azote-metal, rayon covalent, masse rtduite.

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Section: Far-infrared Regionsupporting

confidence: 59%

Vibrational and electronic spectra of new liposoluble metalloporphyrins in a nonpolar noncoordinating solvent

Ringuet¹,

Girard²,

Chapados³

1991

Can. J. Chem.

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“…4B, line a) in analogy to the 7-formyl CAO band of Chl b (29). Indeed, the Raman spectrum of Chl d exhibits a 3-formyl CAO peak at 1,659 cm Ϫ1 (30,31).…”

Section: Resultsmentioning

confidence: 89%

Identification of the special pair of photosystem II in a chlorophyll d -dominated cyanobacterium

Tomo

Okubo

Akimoto

et al. 2007

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

125

127

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The composition of photosystem II (PSII) in the chlorophyll (Chl) d-dominated cyanobacterium Acaryochloris marina MBIC 11017 was investigated to enhance the general understanding of the energetics of the PSII reaction center. We first purified photochemically active complexes consisting of a 47-kDa Chl protein (CP47), CP43 (PcbC), D1, D2, cytochrome b 559, PsbI, and a small polypeptide. The pigment composition per two pheophytin (Phe) a molecules was 55 ؎ 7 Chl d, 3.0 ؎ 0.4 Chl a, 17 ؎ 3 ␣-carotene, and 1.4 ؎ 0.2 plastoquinone-9. The special pair was detected by a reversible absorption change at 713 nm (P713) together with a cation radical band at 842 nm. FTIR difference spectra of the specific bands of a 3-formyl group allowed assignment of the special pair. The combined results indicate that the special pair comprises a Chl d homodimer. The primary electron acceptor was shown by photoaccumulation to be Phe a, and its potential was shifted to a higher value than that in the Chl a/Phe a system. The overall energetics of PSII in the Chl d system are adjusted to changes in the redox potentials, with P713 as the special pair using a lower light energy at 713 nm. Taking into account the reported downward shift in the potential of the special pair of photosystem I (P740) in A. marina, our findings lend support to the idea that changes in photosynthetic pigments combine with a modification of the redox potentials of electron transfer components to give rise to an energetic adjustment of the total reaction system. Acaryochloris marina ͉ FTIR ͉ reaction center ͉ photosynthesis ͉ electron transfer C hlorophyll (Chl) a has a ubiquitous role as an electron donor in the photochemical reactions of oxygenic photosynthesis, in which two kinds of photosystem, namely photosystem I (PSI) and photosystem II (PSII), cooperatively drive photosynthetic electron flow from water to NADP ϩ . The reduced cofactor, NADPH, is then used for CO 2 fixation. Chl a is a key pigment that serves as an electron donor called the special pair in PSI and PSII. Acaryochloris spp. are unique cyanobacteria that differ from the majority of photosynthetic organisms by having Chl d (3-desvinyl-3-formyl Chl a) (1-4) as the major pigment (Ͼ95%); Chl a is a minor component but is never absent (5, 6). In photosynthetic organisms, changes in pigment composition affect both the function of pigments and their reaction environments, including the modified proteins that accommodate them. Photosynthetic pigments function in two roles: as lightharvesting components and as electron transfer components. Light harvesting is mainly governed by the orientation and energy levels of pigments, and, in this context, a particular excitation energy level is not an absolute precondition for function, but a relative one. On the other hand, electron transfer reactions are governed by an absolute redox potential, because the photosynthetic oxidation of water requires a very high potential, whereas reduction of NADP ϩ requires a very low potential. For this reason, it is of particul...

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“…It is thought that this band is indicative of pentacoordinated Chl-a (32,33). The fact that the 1608 cm -1 band is modified upon mutation therefore suggests some coordination modifications of P A and P B .…”

Section: In the Ftir Ds Inmentioning

confidence: 96%

Mutation Induced Modulation of Hydrogen Bonding to P700 Studied Using FTIR Difference Spectroscopy

et al. 2003

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Site-directed mutagenesis in combination with Fourier transform infrared difference spectroscopy has been used to study how hydrogen bonding modulates the electronic and physical organization of P700, the primary electron donor in photosystem I. Wild-type PS I particles from Chlamydomonas reinhardtii and a mutant in which ThrA739 is changed to alanine [TA(A739) mutant] were studied. ThrA739 is thought to provide a hydrogen bond to the chlorophyll-a′ molecule of P700 (the two chlorophylls of P700 (P700 + ) will be called P A and P B (P A + and P B + )). The mutation considerably alters the (P700 + -P700) FTIR difference spectra. However, we were able to describe all of the mutation induced changes in the difference spectra in terms of difference band assignments that were proposed recently (Hastings, G., Ramesh, V. M., Wang, R., Sivakumar, V. and Webber, A. (2001) Biochemistry 40, 12943-12949). Upon comparison of mutant and wild type (P700 + -P700) FTIR difference spectra, it is shown that (1) the 13 3 ester carbonyl modes of P A and P B are unaltered upon mutation of ThrA739 to alanine. (2) The 13 3 ester carbonyl modes of P A + /P B + upshift/downshift upon mutation. These oppositely directed shifts indicate that the mutation modifies the charge distribution over the pigments in the P700 + state, with charge on P B being relocated onto P A . We also show that the 13 1 keto carbonyl mode of P B /P B + is unaltered/ downshifted upon mutation, as is expected for the above-described mutation induced charge redistribution in P700 + . Although the 13 3 ester carbonyl modes of the chlorophylls of P700 in the ground state are unaltered upon mutation, the 13 1 keto carbonyl mode of P A upshifts upon mutation, as does the 13 1 keto carbonyl mode of P A + . For P700 in the ground state, bands that we associate with HisA676/HisB656 upshift/downshift upon mutation. For the P700 + state, bands that we associate with HisA676/HisB656 also upshift/downshift upon mutation. These observations are also consistent with the notion that the mutation leads to the charge on P B + being relocated onto P A + . In addition, we suggest that a hydrogen bond to the 13 1 keto carbonyl of P A is still present in the TA(A739) mutant, probably mediated through an introduced water molecule.

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Resonance Raman and infrared studies on axial coordination to chlorophylls a and b in vitro

Cited by 137 publications

References 0 publications

Vibrational and electronic spectra of new liposoluble metalloporphyrins in a nonpolar noncoordinating solvent

Vibrational and electronic spectra of new liposoluble metalloporphyrins in a nonpolar noncoordinating solvent

Identification of the special pair of photosystem II in a chlorophyll d -dominated cyanobacterium

Mutation Induced Modulation of Hydrogen Bonding to P700 Studied Using FTIR Difference Spectroscopy

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