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Polarization angle dependence of stark absorption spectra of spirilloxanthin bound to the reconstituted LH1 complexes using LH1-subunits isolated from the purple photosynthetic bacterium Rhodospirillum rubrum

100%

Horibe T., Nakagawa K., Kusumoto T., Fujii R., Cogdell R. J., Nango M., Hashimoto H.

Acta Biochimica Polonica

2012

tom 59

nr 1

Reconstituted LH1 complexes were prepared using the LH1 subunit-type complexes, isolated from the purple photosynthetic bacterium Rhodospirillum (Rs.) rubrum, and purified all-trans spirilloxanthin. Stark absorption spectra of spirilloxanthin bound to both the native and reconstituted LH1 complexes were compared in different polarization angles (χ) against the external electric field. From the polarization angle dependence of the Stark absorption spectra, two angles were determined in reference to the direction of transition dipole moment (m) of spirilloxanthin: one is the change in polarizability upon photoexcitation (Δα), θΔα and the other is the change in static dipole moment upon photoexcitation (Δμ), θΔμ. Despite the symmetric molecular structure of all-trans spirilloxanthin, its Stark absorption spectra show pronounced values of Δμ. This large Δμ values essentially caused by the effect of induced dipole moment through Δα both in the cases for native and reconstituted LH1 complexes. However, slightly different values of θΔα and θΔμ observed for the native LH1 complex suggest that spirilloxanthin is asymmetrically distorted when bound to the native LH1 complex and gives rise to intrinsic Δμ value.

Formation of lipid droplets induced by 2,3-dihydrogeranylgeranoic acid distinct from geranylgeranoic acid

84%

Kodaira Y., Kusumoto T., Takahashi T., Matsumura Y., Miyagi Y., Okamoto K., Shidoji Y., Sagami H.

Acta Biochimica Polonica

2007

tom 54

nr 4

777-782

Geranylgeranoic acid (GGA) and 2,3-dihydrogeranylgeranoic acid (2,3-diGGA) are geranylgerani-ol-derived metabolites (Kodaira et al.(2002) J Biochem132:327–334). In the present study, we examined the effects of these acids on HL-60 cells. The cells were differentiated into neutrophils by GGA stimulation like retinoic acid stimulation. In the case of cells stimulated with 2,3-diGGA, neutrophils were not detected, but the formation of lipid droplets was induced. On the other hand, when the cells were cultured in the presence of 0.1% FBS instead of 10% FBS, apoptotic cells were induced not only by GGA stimulation but also with 2,3-diGGA. In the latter case, when the cells were cultured in the co-presence of a caspase-3 inhibitor (Ac-DMQD-CHO), the lipid droplets formation was observed in the cells. These results suggest that GGA and 2,3-diGGA are extremely different from each other with respect to their effects on HL-60 cells.

Ograniczanie wyników

2 Acta Biochimica Polonica

2 Kusumoto T.

1 Cogdell R. J.

1 Fujii R.

1 Hashimoto H.

1 Horibe T.

1 Kodaira Y.

1 Matsumura Y.

1 Miyagi Y.

1 Nakagawa K.

1 Nango M.

1 Okamoto K.

1 Sagami H.

1 Shidoji Y.

1 Takahashi T.

1 2012

1 2007

Wyniki wyszukiwania

Polarization angle dependence of stark absorption spectra of spirilloxanthin bound to the reconstituted LH1 complexes using LH1-subunits isolated from the purple photosynthetic bacterium Rhodospirillum rubrum

Formation of lipid droplets induced by 2,3-dihydrogeranylgeranoic acid distinct from geranylgeranoic acid