Directed assembly of defined oligomeric photosynthetic reaction centres through adaptation with programmable extra-membrane coiled-coil interfaces.
A challenge associated with the utilisation of bioenergetic proteins in new, synthetic energy transducing systems is achieving efficient and predictable self-assembly of individual components, both natural and man-made, into a functioning macromolecular system. Despite progress with water-soluble proteins, the challenge of programming self-assembly of integral membrane proteins into non-native macromolecular architectures remains largely unexplored. In this work it is shown that the assembly of dimers, trimers or tetramers of the naturally monomeric purple bacterial reaction centre can be directed by augmentation with an α-helical peptide that self-associates into extra-membrane coiled-coil bundle. Despite this induced oligomerisation the assembled reaction centres displayed normal spectroscopic properties, implying preserved structural and functional integrity. Mixing of two reaction centres modified with mutually complementary α-helical peptides enabled the assembly of heterodimers in vitro, pointing to a generic strategy for assembling hetero-oligomeric complexes from diverse modified or synthetic components.Addition of two coiled-coil peptides per reaction centre monomer was also tolerated despite the challenge presented to the pigment-protein assembly machinery of introducing multiple self-associating sequences. These findings point to a generalised approach where oligomers or longer range assemblies of multiple light harvesting and/or redox proteins can be constructed in a manner that can be genetically-encoded, enabling the construction of new, designed bioenergetic systems in vivo or in vitro.
School of Biochemistry, Medical Sciences Building, University of Bristol, University Walk, Bristol BS8 1TD, United Kingdom.
David J K
DJ
Swainsbury
School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, United Kingdom.
Robert L
RL
Harniman
School of Biochemistry, Medical Sciences Building, University of Bristol, University Walk, Bristol BS8 1TD, United Kingdom.
Natalie D
ND
Di Bartolo
School of Biochemistry, Medical Sciences Building, University of Bristol, University Walk, Bristol BS8 1TD, United Kingdom.
Juntai
J
Liu
School of Biochemistry, Medical Sciences Building, University of Bristol, University Walk, Bristol BS8 1TD, United Kingdom.
William F M
WF
Harper
School of Biochemistry, Medical Sciences Building, University of Bristol, University Walk, Bristol BS8 1TD, United Kingdom.
Alexander S
AS
Corrie
School of Biochemistry, Medical Sciences Building, University of Bristol, University Walk, Bristol BS8 1TD, United Kingdom. Electronic address: m.r.jones@bristol.ac.uk.
Michael R
MR
Jones
D000222:Adaptation, Physiological; D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism* / Q000528:radiation effects; D004734:Energy Metabolism / Q000528:radiation effects; D007700:Kinetics; D008027:Light; D045342:Light-Harvesting Protein Complexes / Q000737:chemistry / Q000378:metabolism* / Q000528:radiation effects; D056004:Molecular Dynamics Simulation; D010788:Photosynthesis / Q000528:radiation effects; D045322:Photosynthetic Reaction Center Complex Proteins / Q000737:chemistry / Q000378:metabolism* / Q000528:radiation effects; D000072756:Protein Conformation, alpha-Helical; D055503:Protein Multimerization; D020560:Proteobacteria / Q000378:metabolism* / Q000528:radiation effects; D013329:Structure-Activity Relationship
D001426:Bacterial Proteins; D045342:Light-Harvesting Protein Complexes; D045322:Photosynthetic Reaction Center Complex Proteins; C096433:PufL protein, Bacteria; C098543:PufM protein, Bacteria
Coiled-coil; Directed self-assembly; Membrane protein; Oligomerisation; Photosystem; Reaction centre