Statistical considerations on the formation of circular photosynthetic light-harvesting complexes from Rhodopseudomonas palustris

Taniguchi, M., Henry, S., Cogdell, R. J. and Lindsey, J. S. (2014) Statistical considerations on the formation of circular photosynthetic light-harvesting complexes from Rhodopseudomonas palustris. Photosynthesis Research, 121(1), pp. 49-60. (doi: 10.1007/s11120-014-9975-x)

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Abstract

Depending on growth conditions, some species of purple photosynthetic bacteria contain peripheral light-harvesting (LH2) complexes that are heterogeneous owing to the presence of different protomers (containing different αβ-apoproteins). Recent spectroscopic studies of Rhodopseudomonas palustris grown under low-light conditions suggest the presence of a C 3-symmetric LH2 nonamer comprised of two distinct protomers. The software program Cyclaplex, which enables generation and data-mining of virtual libraries of molecular rings formed upon combinatorial reactions, has been used to delineate the possible number and type of distinct nonamers as a function of numbers of distinct protomers. The yield of the C 3-symmetric nonamer from two protomers (A and B in varying ratios) has been studied under the following conditions: (1) statistical, (2) enriched (preclusion of the B-B sequence), and (3) seeded (pre-formation of an A-B-A block). The yield of C 3-symmetric nonamer is at most 0.98 % under statistical conditions versus 5.6 % under enriched conditions, and can be dominant under conditions of pre-seeding with an A-B-A block. In summary, the formation of any one specific nonamer even from only two protomers is unlikely on statistical grounds but must stem from enhanced free energy of formation or a directed assembly process by as-yet unknown factors.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Henry, Dr Sarah and Cogdell, Professor Richard
Authors: Taniguchi, M., Henry, S., Cogdell, R. J., and Lindsey, J. S.
College/School:College of Medical Veterinary and Life Sciences > School of Molecular Biosciences
Journal Name:Photosynthesis Research
Publisher:Springer Netherlands
ISSN:0166-8595
ISSN (Online):1573-5079

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
502614Photosynthetic Antenna Research Center (PARC)Richard CogdellUS Department of Energy (DEN)UNSPECIFIEDRI MOLECULAR CELL & SYSTEMS BIOLOGY