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Gifford LB, Melikyan GB. HIV-1 Capsid Uncoating Is a Multistep Process That Proceeds through Defect Formation Followed by Disassembly of the Capsid Lattice. ACS NANO 2024; 18:2928-2947. [PMID: 38241476 PMCID: PMC10832047 DOI: 10.1021/acsnano.3c07678] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Revised: 01/17/2024] [Accepted: 01/17/2024] [Indexed: 01/21/2024]
Abstract
The HIV-1 core consists of a cone-shaped capsid shell made of capsid protein (CA) hexamers and pentamers encapsulating the viral genome. HIV-1 capsid disassembly, referred to as uncoating, is important for productive infection; however, the location, timing, and regulation of uncoating remain controversial. Here, we employ amber codon suppression to directly label CA. In addition, a fluid phase fluorescent probe is incorporated into the viral core to detect small defects in the capsid lattice. This double-labeling strategy enables the visualization of uncoating of single cores in vitro and in living cells, which we found to always proceed through at least two distinct steps─the formation of a defect in the capsid lattice that initiates gradual loss of CA below a detectable level. Importantly, intact cores containing the fluid phase and CA fluorescent markers enter and uncoat in the nucleus, as evidenced by a sequential loss of both markers, prior to establishing productive infection. This two-step uncoating process is observed in different cells, including a macrophage line. Notably, the lag between the release of fluid phase marker and terminal loss of CA appears to be independent of the cell type or reverse transcription and is much longer (>5-fold) for nuclear capsids compared to cell-free cores or cores in the cytosol, suggesting that the capsid lattice is stabilized by capsid-binding nuclear factors. Our results imply that intact HIV-1 cores enter the cell nucleus and that uncoating is initiated through a localized defect in the capsid lattice prior to a global loss of CA.
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Affiliation(s)
- Levi B. Gifford
- Department
of Pediatrics, Emory University School of
Medicine, Atlanta, Georgia 30322, United States
| | - Gregory B. Melikyan
- Department
of Pediatrics, Emory University School of
Medicine, Atlanta, Georgia 30322, United States
- Children’s
Healthcare of Atlanta, Atlanta, Georgia 30322, United States
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Reinkemeier CD, Lemke EA. Synthetic Organelles for Multiple mRNA Selective Genetic Code Expansions in Eukaryotes. Methods Mol Biol 2023; 2563:341-369. [PMID: 36227482 DOI: 10.1007/978-1-0716-2663-4_17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Engineering new functionalities into living eukaryotic systems is one of the main goals of synthetic biology. To this end, often enzyme evolution or de novo protein design is employed, which each have their own advantages and disadvantages. As complimentary tools, we recently developed orthogonally translating and film-like synthetic organelles that allow to create new enzyme functionalities based on spatial separation. We applied this technology to genetic code expansion (GCE) and showed that it is possible to equip eukaryotic cells with multiple orthogonal genetic codes that enable the specific reprogramming of distinct translational machineries, each with single-residue precision.In this protocol, we describe how synthetic organelles can be used to perform mRNA selective GCE and how they can be further developed to allow the simultaneous incorporation of distinct noncanonical amino acids (ncAAs) into selected proteins and how this can be used to label proteins selectively with fluorescent dyes via bioorthogonal chemistry.
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Affiliation(s)
- Christopher D Reinkemeier
- Biocentre, Departments of Biology and Chemistry, Johannes Gutenberg University Mainz, Mainz, Germany
- Institute of Molecular Biology gGmbH, Mainz, Germany
| | - Edward A Lemke
- Biocentre, Departments of Biology and Chemistry, Johannes Gutenberg University Mainz, Mainz, Germany.
- Institute of Molecular Biology gGmbH, Mainz, Germany.
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Joest EF, Winter C, Wesalo JS, Deiters A, Tampé R. Efficient Amber Suppression via Ribosomal Skipping for In Situ Synthesis of Photoconditional Nanobodies. ACS Synth Biol 2022; 11:1466-1476. [PMID: 35060375 PMCID: PMC9157392 DOI: 10.1021/acssynbio.1c00471] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Genetic code expansion is a versatile method for in situ synthesis of modified proteins. During mRNA translation, amber stop codons are suppressed to site-specifically incorporate non-canonical amino acids. Thus, nanobodies can be equipped with photocaged amino acids to control target binding on demand. The efficiency of amber suppression and protein synthesis can vary with unpredictable background expression, and the reasons are hardly understood. Here, we identified a substantial limitation that prevented synthesis of nanobodies with N-terminal modifications for light control. After systematic analyses, we hypothesized that nanobody synthesis was severely affected by ribosomal inaccuracy during the early phases of translation. To circumvent a background-causing read-through of a premature stop codon, we designed a new suppression concept based on ribosomal skipping. As an example, we generated intrabodies with photoactivated target binding in mammalian cells. The findings provide valuable insights into the genetic code expansion and describe a versatile synthesis route for the generation of modified nanobodies that opens up new perspectives for efficient site-specific integration of chemical tools. In the area of photopharmacology, our flexible intrabody concept builds an ideal platform to modulate target protein function and interaction.
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Affiliation(s)
- Eike F Joest
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Max-von-Laue-Str. 9, 60438 Frankfurt/M, Germany
| | - Christian Winter
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Max-von-Laue-Str. 9, 60438 Frankfurt/M, Germany
| | - Joshua S Wesalo
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA
| | - Alexander Deiters
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA
| | - Robert Tampé
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Max-von-Laue-Str. 9, 60438 Frankfurt/M, Germany
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Galindo Casas M, Stargardt P, Mairhofer J, Wiltschi B. Decoupling Protein Production from Cell Growth Enhances the Site-Specific Incorporation of Noncanonical Amino Acids in E. coli. ACS Synth Biol 2020; 9:3052-3066. [PMID: 33150786 DOI: 10.1021/acssynbio.0c00298] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The site-specific incorporation of noncanonical amino acids (ncAAs) into proteins by amber stop codon suppression has become a routine method in academic laboratories. This approach requires an amber suppressor tRNACUA to read the amber codon and an aminoacyl-tRNA synthetase to charge the tRNACUA with the ncAA. However, a major drawback is the low yield of the mutant protein in comparison to the wild type. This effect primarily results from the competition of release factor 1 with the charged suppressor tRNACUA for the amber codon at the A-site of the ribosome. A number of laboratories have attempted to improve the incorporation efficiency of ncAAs with moderate results. We aimed at increasing the efficiency to produce high yields of ncAA-functionalized proteins in a scalable setting for industrial application. To do this, we inserted an ncAA into the enhanced green fluorescent protein and an antibody mimetic molecule using an industrial E. coli strain, which produces recombinant proteins independent of cell growth. The controlled decoupling of recombinant protein production from cell growth considerably increased the incorporation of the ncAA, producing substantially higher protein yields versus the reference E. coli strain BL21(DE3). The target proteins were expressed at high levels, and the ncAA was efficiently incorporated with excellent fidelity while the protein function was preserved.
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Affiliation(s)
- Meritxell Galindo Casas
- acib − Austrian Center of Industrial Biotechnology, 8010 Graz, Austria
- Institute of Molecular Biotechnology, Graz University of Technology, 8010 Graz, Austria
| | | | | | - Birgit Wiltschi
- acib − Austrian Center of Industrial Biotechnology, 8010 Graz, Austria
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Scherr J, Tang Z, Küllmer M, Balser S, Scholz AS, Winter A, Parey K, Rittner A, Grininger M, Zickermann V, Rhinow D, Terfort A, Turchanin A. Smart Molecular Nanosheets for Advanced Preparation of Biological Samples in Electron Cryo-Microscopy. ACS NANO 2020; 14:9972-9978. [PMID: 32589396 DOI: 10.1021/acsnano.0c03052] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Transmission electron cryo-microscopy (cryoEM) of vitrified biological specimens is a powerful tool for structural biology. Current preparation of vitrified biological samples starts off with sample isolation and purification, followed by the fixation in a freestanding layer of amorphous ice. Here, we demonstrate that ultrathin (∼10 nm) smart molecular nanosheets having specific biorecognition sites embedded in a biorepulsive layer covalently bound to a mechanically stable carbon nanomembrane allow for a much simpler isolation and structural analysis. We characterize in detail the engineering of these nanosheets and their biorecognition properties employing complementary methods such as X-ray photoelectron and infrared spectroscopy, atomic force microscopy as well as surface plasmon resonance measurements. The desired functionality of the developed nanosheets is demonstrated by in situ selection of a His-tagged protein from a mixture and its subsequent structural analysis by cryoEM.
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Affiliation(s)
- Julian Scherr
- Department of Chemistry, University of Frankfurt, Max-von-Laue-Str. 7, 60438 Frankfurt, Germany
| | - Zian Tang
- Institute of Physical Chemistry, Friedrich Schiller University Jena, Lessingstr. 10, 07743 Jena, Germany
| | - Maria Küllmer
- Institute of Physical Chemistry, Friedrich Schiller University Jena, Lessingstr. 10, 07743 Jena, Germany
| | - Sebastian Balser
- Department of Chemistry, University of Frankfurt, Max-von-Laue-Str. 7, 60438 Frankfurt, Germany
| | - Alexander Stefan Scholz
- Department of Chemistry, University of Frankfurt, Max-von-Laue-Str. 7, 60438 Frankfurt, Germany
| | - Andreas Winter
- Institute of Physical Chemistry, Friedrich Schiller University Jena, Lessingstr. 10, 07743 Jena, Germany
| | - Kristian Parey
- Department of Structural Biology, Max Planck Institute of Biophysics, Max-von-Laue-Str. 3, 60438 Frankfurt, Germany
| | - Alexander Rittner
- Institute of Organic Chemistry and Chemical Biology, Buchmann Institute for Molecular Life Sciences, University of Frankfurt, Max-von-Laue-Str. 15, 60438 Frankfurt, Germany
| | - Martin Grininger
- Institute of Organic Chemistry and Chemical Biology, Buchmann Institute for Molecular Life Sciences, University of Frankfurt, Max-von-Laue-Str. 15, 60438 Frankfurt, Germany
| | - Volker Zickermann
- Institute of Biochemistry II, Medical School, University of Frankfurt, Max-von-Laue-Str. 9, 60438 Frankfurt, Germany
| | - Daniel Rhinow
- Department of Structural Biology, Max Planck Institute of Biophysics, Max-von-Laue-Str. 3, 60438 Frankfurt, Germany
| | - Andreas Terfort
- Department of Chemistry, University of Frankfurt, Max-von-Laue-Str. 7, 60438 Frankfurt, Germany
| | - Andrey Turchanin
- Institute of Physical Chemistry, Friedrich Schiller University Jena, Lessingstr. 10, 07743 Jena, Germany
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