title: Absorption and CD spectroscopy and modeling of various LH2 complexes from purple bacteria.
abstract: 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.
authors.affiliation: Department of Biophysics and Physics of Complex Systems, Vrije Universiteit, 1081 HV Amsterdam, The Netherlands.
authors.forename: Sofia
authors.initials: S
authors.lastname: Georgakopoulou
authors.forename: Raoul N
authors.initials: RN
authors.lastname: Frese
authors.forename: Evelyn
authors.initials: E
authors.lastname: Johnson
authors.forename: Corline
authors.initials: C
authors.lastname: Koolhaas
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Cogdell
authors.forename: Rienk
authors.initials: R
authors.lastname: van Grondelle
authors.forename: Gert
authors.initials: G
authors.lastname: van der Zwan
mesh_terms: 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
chemical_list: C081521:B800-850 light-harvesting complex, bacteria; D001426:Bacterial Proteins; D003902:Detergents; D045342:Light-Harvesting Protein Complexes; D045322:Photosynthetic Reaction Center Complex Proteins