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Title: Direct Imaging of Protein Organization in an Intact Bacterial Organelle Using High-Resolution Atomic Force Microscopy

Journal Article · · ACS Nano

The function of bioenergetic membranes is strongly influenced by the spatial arrangement of their constituent membrane proteins. Atomic force microscopy (AFM) can be used to probe protein organization at high resolution, allowing individual proteins to be identified. However, previous AFM studies of biological membranes have typically required that curved membranes are ruptured and flattened during sample preparation, with the possibility of disruption of the native protein arrangement or loss of proteins. Imaging native, curved membranes requires minimal tip–sample interaction in both lateral and vertical directions. Here, long-range tip–sample interactions are reduced by optimizing the imaging buffer. Tapping mode AFM with high-resonance-frequency small and soft cantilevers, in combination with a high-speed AFM, reduces the forces due to feedback error and enables application of an average imaging force of tens of piconewtons. Using this approach, we have imaged the membrane organization of intact vesicular bacterial photosynthetic “organelles”, chromatophores. Despite the highly curved nature of the chromatophore membrane and lack of direct support, the resolution was sufficient to identify the photosystem complexes and quantify their arrangement in the native state. Successive imaging showed the proteins remain surprisingly static, with minimal rotation or translation over several-minute time scales. High-order assemblies of RC-LH1-PufX complexes are observed, and intact ATPases are successfully imaged. The methods developed here are likely to be applicable to a broad range of protein-rich vesicles or curved membrane systems, which are an almost ubiquitous feature of native organelles.

Research Organization:
Energy Frontier Research Centers (EFRC) (United States). Photosynthetic Antenna Research Center (PARC)
Sponsoring Organization:
USDOE Office of Science (SC), Basic Energy Sciences (BES); Engineering and Physical Sciences Research Council (EPSRC); Biotechnology and Biological Sciences Research Council (BBSRC) (United Kingdom); European Research Council (ERC)
Grant/Contract Number:
SC 0001035; SC0001035; EP/I012060/1; BB/L014904/1; EP/M027430/1; BB/M00026/1; 338895
OSTI ID:
1333026
Alternate ID(s):
OSTI ID: 1388745
Journal Information:
ACS Nano, Journal Name: ACS Nano Vol. 11 Journal Issue: 1; ISSN 1936-0851
Publisher:
American Chemical Society (ACS)Copyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 33 works
Citation information provided by
Web of Science

References (33)

Molecular Architecture of the Rotary Motor in ATP Synthase journal November 1999
The architecture of Rhodobacter sphaeroides chromatophores journal August 2014
Short cantilevers for atomic force microscopy journal October 1996
Inhibitor-complexed Structures of the Cytochrome bc 1 from the Photosynthetic Bacterium Rhodobacter sphaeroides journal November 2007
Atomic Force Microscopy with Nanoscale Cantilevers Resolves Different Structural Conformations of the DNA Double Helix journal June 2012
Organization and Regulation of Mitochondrial Protein Synthesis journal June 2016
Integration of energy and electron transfer processes in the photosynthetic membrane of Rhodobacter sphaeroides journal October 2014
Fractured polymer/silica fiber surface studied by tapping mode atomic force microscopy journal June 1993
Adaptation of intracytoplasmic membranes to altered light intensity in Rhodobacter sphaeroides journal September 2012
Proteoliposomes in nanobiotechnology journal January 2012
Tip motion in amplitude modulation (tapping-mode) atomic-force microscopy: Comparison between continuous and point-mass models journal March 2002
Dynamics and Diffusion in Photosynthetic Membranes from Rhodospirillum Photometricum journal November 2006
The Interplay between Cell Wall Mechanical Properties and the Cell Cycle in Staphylococcus aureus journal December 2014
Electrostatically Balanced Subnanometer Imaging of Biological Specimens by Atomic Force Microscope journal February 1999
Atomic-level structural and functional model of a bacterial photosynthetic membrane vesicle journal September 2007
Monomeric RC–LH1 core complexes retard LH2 assembly and intracytoplasmic membrane formation in PufX-minus mutants of Rhodobacter sphaeroides journal September 2011
Dimerization of core complexes as an efficient strategy for energy trapping in Rhodobacter sphaeroides journal June 2016
The native architecture of a photosynthetic membrane journal August 2004
Förster Energy Transfer Theory as Reflected in the Structures of Photosynthetic Light‐Harvesting Systems journal February 2011
Small cantilevers for force spectroscopy of single molecules journal August 1999
Imaging the membrane protein bacteriorhodopsin with the atomic force microscope journal December 1990
Quinone Pathways in Entire Photosynthetic Chromatophores of Rhodospirillum photometricum journal October 2009
Three-Dimensional Structure of the Rhodobacter sphaeroides RC-LH1-PufX Complex: Dimerization and Quinone Channels Promoted by PufX journal October 2013
Three-dimensional Reconstruction of a Membrane-bending Complex journal March 2008
Trapping Kinetics in Mutants of the Photosynthetic Purple Bacterium Rhodobacter sphaeroides: Influence of the Charge Separation Rate and Consequences for the Rate-Limiting Step in the Light-Harvesting Process journal March 1994
Membrane invagination in Rhodobacter sphaeroides is initiated at curved regions of the cytoplasmic membrane, then forms both budded and fully detached spherical vesicles: Membrane biogenesis in Rba. sphaeroides journal April 2010
Tapping mode atomic force microscopy in liquids journal March 1994
Tip-surface forces, amplitude, and energy dissipation in amplitude-modulation (tapping mode) force microscopy journal October 2001
Energy-transfer dynamics in three light-harvesting mutants of Rhodobacter sphaeroides: a picosecond spectroscopy study journal April 1990
The Organization of LH2 Complexes in Membranes from Rhodobacter sphaeroides journal August 2008
Carotenoids are essential for normal levels of dimerisation of the RC–LH1–PufX core complex of Rhodobacter sphaeroides: Characterisation of R-26 as a crtB (phytoene synthase) mutant journal September 2011
Light Harvesting by Lamellar Chromatophores in Rhodospirillum photometricum journal June 2014
Adsorption of Biological Molecules to a Solid Support for Scanning Probe Microscopy journal July 1997