[PDF]    http://dx.doi.org/10.3952/lithjphys.47116

Open access article / Atviros prieigos straipsnis

Lith. J. Phys. 47, 103–108 (2007)


GAUSSIAN DECOMPOSITION OF ABSORPTION SPECTRA OF PERIPHERAL LIGHT-HARVESTING COMPLEXES OF PHOTOSYNTHETIC BACTERIA
V. Urbonienėa, O. Vrublevskajab, G. Trinkūnasb, M. Stakvilevičiusc, A. Galld, B. Robertd, and L. Valkūnasb,e
aDepartment of General Physics and Spectroscopy, Vilnius University, Saulėtekio 9, LT-10222 Vilnius, Lithuania
E-mail: vidita.urbo@gmail.com
bInstitute of Physics, Savanorių 231, LT-02300 Vilnius, Lithuania
cDepartment of Mathematics, Šiauliai University, Višinskio 19, LT-77156 Šiauliai, Lithuania
dInstitut de Biologie et Technologie de Saclay, C.E.A. Saclay, 91191 Gif-sur-Yvette Cedex, France
eDepartment of Theoretical Physics, Vilnius University, Saulėtekio 9, LT-10222 Vilnius, Lithuania

Received 25 January 2007

The absorption spectra of light-harvesting complexes (LH2) purified from Rhodobacter sphaeroides in 60% glycerol measured in the 4–300 K temperature range have been analysed in terms of linear combination of symmetric Gaussian subbands. All absorption spectra of LH2 are well fitted with sixteen Gaussian subbands. To attribute them to the B800 and B850 bands, the ratio of the integral intensity of those bands is considered, assuming that it should be close to 2 and independent of temperature. From the analysis of the B850 absorption spectrum it is concluded that the maximal value of the resonance interaction between the pigments in the B850 ring should be 300 and 310 cm–1 at room temperature and 4 K, respectively.
Keywords: absorption spectra, peripheral light-harvesting pigment-protein complex, photosynthetic bacteria, Gaussian decomposition
PACS: 71.35.-y, 87.15.-v, 87.15.Aa


FOTOSINTETINANČIŲ BAKTERIJŲ PERIFERINIŲ ŠVIESĄ SURENKANČIŲ KOMPLEKSŲ SUGERTIES SPEKTRŲ SKAIDYMAS GAUSO SANDAIS
V. Urbonienėa, O. Vrublevskajab, G. Trinkūnasb, M. Stakvilevičiusc, A. Galld, B. Robertd, and L. Valkūnasb,e
aVilniaus universitetas, Vilnius, Lietuva
bFizikos institutas, Vilnius, Lietuva
cŠiaulių universitetas, Šiauliai, Lietuva
dC.E.A. Saclay, Prancūzija

Periferinių šviesą surenkančių kompleksų LH2, išskirtų iš Rhodobacter sphaeroides fotosintetinančių bakterijų, esančių 60 % Tris[hidrometil]aminometano (Tris. Cl)/glicerolio buferyje, sugerties spektrų kontūrai išskaidyti Gauso sandais. Visi sugerties spektrai buvo aproksimuoti šešiolikos Gauso sandų sumos funkcija. Gauso sandai buvo priskirti B800 ir B850 sugerties juostoms, padarius prielaidą, kad šių juostų integralinio intensyvumo santykis turi būti maždaug 2 ir nepriklausyti nuo temperatūros.
Gauso sandai, priskirti B850 sugerties juostoms, leido įvertinti tankiau išdėstytų bakteriochlorofilo pigmentų rezonansinę sąveiką, kurios dydis 300 cm–1 kambario temperatūroje ir 310 cm–1 4 K temperatūroje. Šią nežymią rezonansinės sąveikos priklausomybę nuo temperatūros galima aiškinti tirpiklio dielektrinės konstantos priklausomybe nuo temperatūros.


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