Hypothesis on origin of three bands in absorption spectrum of new type LH2 complex (B800-830-850) from Thiorhodospira sibiricaстатья
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Статья опубликована в журнале из перечня ВАК
Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 18 июля 2013 г.
Аннотация:A model of spatial arrangement and mutual orientation of bacteriochlorophyll (BChl) molecules in peripheral light-harvesting complex LH2 from purple bacterium Thiorhodospira sibirica is proposed. Absorption and circular dichroism spectra were calculated on the basis of LH2 structure in two other bacteria, known from X-ray data, and exciton theory for circular aggregates of BChls. It was assumed that BChl molecules in LH2 complex from Tsr. sibirica form trimers, which include two adjacent BChl molecules of the B850 ring (Bchl850) and one close BChl molecule of the B800 ring (BChl800). The expected orientation of BChl molecules within the trimer provides lower interaction between the adjacent BChl850 molecules rather than between BChl800 molecule and each of two BChl850 molecules. According to calculations the short-wavelength band with a peak at 800 nm occurs mainly due to interaction between BChl850alpha and BChl800 molecules, the long-wavelength band at 860 nm, due to interaction between BChl850beta and BChl800 molecules, and the band at 830 nm, due to interaction of BChl800 molecules and BChl850alpha with BChl850beta. Three-peak absorption spectra are available for confined set of spatial arrangements and mutual orientations of BChl molecules.