SPECTROSCOPIC PROPERTIES OF THE LIGHT-HARVESTING COMPLEXES FROM RHODOSPIRILLUM-MOLISCHIANUM

Spectroscopic properties, including low-temperature absorbance, linear and circular dichroism and site-selection fluorescence of the antenna complexes from Rhodospirillum molischianum have been determined. The unique 'LH1-like' character of the amino acid sequence from LH2 of thi s bacterium is reflected in the circular dichroism of the B850 band of this complex. The wavelength dependence of the polarization of the LH 2 complex shows an unusual shape that is attributed to the octameric s tate of this complex. The complete amino acid sequence for the LH1 alp ha-polypeptide and most of the beta-polypeptides are presented. These conform to the general features of other LH1 polypeptides, This result , in combination with spectroscopic data for LH1 imply that the organi sation of the core in this bacterium is not much different from that i n other purple non-sulphur bacteria.