Absorption and CD spectroscopy and modeling of various LH2 complexes from purple bacteria.
The absorption (OD) and circular dichroism (CD) spectra of LH2 complexes from various purple bacteria have been measured and modeled. Based on the lineshapes of the spectra we can sort the LH2 complexes into two distinguishable groups: "acidophila"-like (type 1) and "molischianum"-like (type 2). Starting from the known geometric structures of Rhodopseudomonas (Rps.) acidophila and Rhodospirillum (Rsp.) molischianum we can model the OD and CD spectra of all species by just slightly varying some key parameters: the interaction strength, the energy difference of alpha- and beta-bound B850 bacteriochlorophylls (BChls), the orientation of the B800 and B850 BChls, and the (in)homogeneous broadening. Although the ring size can vary, the data are consistent with all the LH2 complexes having basically very similar structures.
Georgakopoulou
Sofia
S
Department of Biophysics and Physics of Complex Systems, Vrije Universiteit, 1081 HV Amsterdam, The Netherlands.
Frese
Raoul N
RN
Johnson
Evelyn
E
Koolhaas
Corline
C
Cogdell
Richard J
RJ
van Grondelle
Rienk
R
van der Zwan
Gert
G
D001426:Bacterial Proteins; D001703:Biophysics / Q000379:methods; D002942:Circular Dichroism; D003902:Detergents / Q000494:pharmacology; D045342:Light-Harvesting Protein Complexes; D045322:Photosynthetic Reaction Center Complex Proteins / Q000737:chemistry*; D011485:Protein Binding; D016992:Rhodobacter / Q000737:chemistry*; D013053:Spectrophotometry / Q000379:methods*; D013696:Temperature
C081521:B800-850 light-harvesting complex, bacteria; D001426:Bacterial Proteins; D003902:Detergents; D045342:Light-Harvesting Protein Complexes; D045322:Photosynthetic Reaction Center Complex Proteins