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Cryo-EM structure of a Ca2+-bound photosynthetic LH1-RC complex containing multiple αβ-polypeptides
- Source :
- Nature Communications, Nature Communications, Vol 11, Iss 1, Pp 1-9 (2020)
- Publication Year :
- 2020
- Publisher :
- Springer Science and Business Media LLC, 2020.
-
Abstract
- The light-harvesting-reaction center complex (LH1-RC) from the purple phototrophic bacterium Thiorhodovibrio strain 970 exhibits an LH1 absorption maximum at 960 nm, the most red-shifted absorption for any bacteriochlorophyll (BChl) a-containing species. Here we present a cryo-EM structure of the strain 970 LH1-RC complex at 2.82 Å resolution. The LH1 forms a closed ring structure composed of sixteen pairs of the αβ-polypeptides. Sixteen Ca ions are present in the LH1 C-terminal domain and are coordinated by residues from the αβ-polypeptides that are hydrogen-bonded to BChl a. The Ca2+-facilitated hydrogen-bonding network forms the structural basis of the unusual LH1 redshift. The structure also revealed the arrangement of multiple forms of α- and β-polypeptides in an individual LH1 ring. Such organization indicates a mechanism of interplay between the expression and assembly of the LH1 complex that is regulated through interactions with the RC subunits inside.<br />Here the authors report a cryo-EM structure of the light-harvesting-reaction center complex (LH1- RC) from the purple phototrophic bacterium Thiorhodovibrio strain 970, providing insights into the mechanisms that underlie the absorbance properties of both the LH1 and the RC of this spectrally unusual purple bacterium.
- Subjects :
- 0301 basic medicine
Cryo-electron microscopy
Stereochemistry
Science
Detergents
Light-Harvesting Protein Complexes
General Physics and Astronomy
010402 general chemistry
Ring (chemistry)
Chromatiaceae
01 natural sciences
Article
General Biochemistry, Genetics and Molecular Biology
Absorbance
03 medical and health sciences
chemistry.chemical_compound
Electron microscopy
Amino Acid Sequence
Photosynthesis
Binding site
lcsh:Science
Peptide sequence
Binding Sites
Multidisciplinary
Strain (chemistry)
Cryoelectron Microscopy
Quinones
Bacteriochlorophyll A
General Chemistry
Lipids
0104 chemical sciences
030104 developmental biology
chemistry
Structural biology
lcsh:Q
Calcium
Bacteriochlorophyll
Peptides
Dimerization
Subjects
Details
- ISSN :
- 20411723
- Volume :
- 11
- Database :
- OpenAIRE
- Journal :
- Nature Communications
- Accession number :
- edsair.doi.dedup.....825acbd50667874db73455c1dfb501f3