Swainsbury, David JK, Faries, Kaitlyn M, Niedzwiedzki, Dariusz M, Martin, Elizabeth C, Flinders, Adam J, Canniffe, Daniel P ORCID: 0000-0002-5022-0437, Shen, Gaozhong, Bryant, Donald A, Kirrnaier, Christine, Holten, Dewey et al (show 1 more authors)
(2019)
Engineering of B800 bacteriochlorophyll binding site specificity in the <i>Rhodobacter sphaeroides</i> LH2 antenna.
BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS, 1860 (3).
pp. 209-223.
This is the latest version of this item.
Text
Swainsbury et al, 2019.pdf - Published version Download (3MB) | Preview |
Abstract
The light-harvesting 2 complex (LH2) of the purple phototrophic bacterium Rhodobacter sphaeroides is a highly efficient, light-harvesting antenna that allows growth under a wide-range of light intensities. In order to expand the spectral range of this antenna complex, we first used a series of competition assays to measure the capacity of the non-native pigments 3-acetyl chlorophyll (Chl) a, Chl d, Chl f or bacteriochlorophyll (BChl) b to replace native BChl a in the B800 binding site of LH2. We then adjusted the B800 site and systematically assessed the binding of non-native pigments. We find that Arg<sub>-10</sub> of the LH2 β polypeptide plays a crucial role in binding specificity, by providing a hydrogen-bond to the 3-acetyl group of native and non-native pigments. Reconstituted LH2 complexes harbouring the series of (B)Chls were examined by transient absorption and steady-state fluorescence spectroscopies. Although slowed 10-fold to ~6 ps, energy transfer from Chl a to B850 BChl a remained highly efficient. We measured faster energy-transfer time constants for Chl d (3.5 ps) and Chl f (2.7 ps), which have red-shifted absorption maxima compared to Chl a. BChl b, red-shifted from the native BChl a, gave extremely rapid (≤0.1 ps) transfer. These results show that modified LH2 complexes, combined with engineered (B)Chl biosynthesis pathways in vivo, have potential for retaining high efficiency whilst acquiring increased spectral range.
Item Type: | Article |
---|---|
Uncontrolled Keywords: | Rhodobacter sphaeroides, LH2, Bacteriochlorophyll, Chlorophyll, Light harvesting, Ligand binding, Protein engineering |
Depositing User: | Symplectic Admin |
Date Deposited: | 31 May 2019 07:59 |
Last Modified: | 09 Oct 2023 19:58 |
DOI: | 10.1016/j.bbabio.2018.11.008 |
Open Access URL: | https://www.sciencedirect.com/science/article/pii/... |
Related URLs: | |
URI: | https://livrepository.liverpool.ac.uk/id/eprint/3043785 |
Available Versions of this Item
-
Engineering of B800 bacteriochlorophyll binding site specificity in the Rhodobacter sphaeroides LH2 antenna. (deposited 04 Feb 2019 16:12)
- Engineering of B800 bacteriochlorophyll binding site specificity in the <i>Rhodobacter sphaeroides</i> LH2 antenna. (deposited 31 May 2019 07:59) [Currently Displayed]