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Wang Z, Zhang QP, Guo F, Ma H, Liang ZH, Yi CH, Zhang C, Chen CF. Self-similar chiral organic molecular cages. Nat Commun 2024; 15:670. [PMID: 38253630 PMCID: PMC10803742 DOI: 10.1038/s41467-024-44922-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Accepted: 01/10/2024] [Indexed: 01/24/2024] Open
Abstract
The endeavor to enhance utility of organic molecular cages involves the evolution of them into higher-level chiral superstructures with self-similar, presenting a meaningful yet challenging. In this work, 2D tri-bladed propeller-shaped triphenylbenzene serves as building blocks to synthesize a racemic 3D tri-bladed propeller-shaped helical molecular cage. This cage, in turn, acts as a building block for a pair of higher-level 3D tri-bladed chiral helical molecular cages, featuring multilayer sandwich structures and displaying elegant characteristics with self-similarity in discrete superstructures at different levels. The evolutionary procession of higher-level cages reveals intramolecular self-shielding effects and exclusive chiral narcissistic self-sorting behaviors. Enantiomers higher-level cages can be interconverted by introducing an excess of corresponding chiral cyclohexanediamine. In the solid state, higher-level cages self-assemble into supramolecular architectures of L-helical or D-helical nanofibers, achieving the scale transformation of chiral characteristics from chiral atoms to microscopic and then to mesoscopic levels.
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Affiliation(s)
- Zhen Wang
- College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, China.
- National Engineering Laboratory for Advanced Yarn and Fabric Formation and Clean Production, Technology Institute, Wuhan Textile University, Wuhan, Hubei, 430200, China.
| | - Qing-Pu Zhang
- College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Fei Guo
- National Engineering Laboratory for Advanced Yarn and Fabric Formation and Clean Production, Technology Institute, Wuhan Textile University, Wuhan, Hubei, 430200, China
| | - Hui Ma
- College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Zi-Hui Liang
- National Engineering Laboratory for Advanced Yarn and Fabric Formation and Clean Production, Technology Institute, Wuhan Textile University, Wuhan, Hubei, 430200, China
| | - Chang-Hai Yi
- National Engineering Laboratory for Advanced Yarn and Fabric Formation and Clean Production, Technology Institute, Wuhan Textile University, Wuhan, Hubei, 430200, China
| | - Chun Zhang
- College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, China.
| | - Chuan-Feng Chen
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Molecular Recognition and Function, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China.
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Machin JM, Kalli AC, Ranson NA, Radford SE. Protein-lipid charge interactions control the folding of outer membrane proteins into asymmetric membranes. Nat Chem 2023; 15:1754-1764. [PMID: 37710048 PMCID: PMC10695831 DOI: 10.1038/s41557-023-01319-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Accepted: 08/08/2023] [Indexed: 09/16/2023]
Abstract
Biological membranes consist of two leaflets of phospholipid molecules that form a bilayer, each leaflet comprising a distinct lipid composition. This asymmetry is created and maintained in vivo by dedicated biochemical pathways, but difficulties in creating stable asymmetric membranes in vitro have restricted our understanding of how bilayer asymmetry modulates the folding, stability and function of membrane proteins. In this study, we used cyclodextrin-mediated lipid exchange to generate liposomes with asymmetric bilayers and characterize the stability and folding kinetics of two bacterial outer membrane proteins (OMPs), OmpA and BamA. We found that excess negative charge in the outer leaflet of a liposome impedes their insertion and folding, while excess negative charge in the inner leaflet accelerates their folding relative to symmetric liposomes with the same membrane composition. Using molecular dynamics, mutational analysis and bioinformatics, we identified a positively charged patch critical for folding and stability. These results rationalize the well-known 'positive-outside' rule of OMPs and suggest insights into the mechanisms that drive OMP folding and assembly in vitro and in vivo.
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Affiliation(s)
- Jonathan M Machin
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK
| | - Antreas C Kalli
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK.
- Leeds Institute of Cardiovascular and Metabolic Medicine, School of Medicine, University of Leeds, Leeds, UK.
| | - Neil A Ranson
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK.
| | - Sheena E Radford
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK.
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Isothermal Titration Calorimetry of Membrane Proteins. Methods Mol Biol 2021. [PMID: 33877623 DOI: 10.1007/978-1-0716-1394-8_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
The ability to quantify protein-protein interactions without adding labels to protein has made isothermal titration calorimetry (ITC) a preferred technique to study proteins in aqueous solution. Here, we describe the application of ITC to the study of protein-protein interactions in membrane mimics using the association of integrin αIIb and β3 transmembrane domains in phospholipid bicelles as an example. A higher conceptual and experimental effort compared to water-soluble proteins is required for membrane proteins and rewarded with rare thermodynamic insight into this central class of proteins.
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