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Das D, Ainavarapu SRK. Protein engineering using circular permutation - structure, function, stability, and applications. FEBS J 2024; 291:3581-3596. [PMID: 38676939 DOI: 10.1111/febs.17146] [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: 10/12/2023] [Revised: 03/13/2024] [Accepted: 04/12/2024] [Indexed: 04/29/2024]
Abstract
Protein engineering is important for creating novel variants from natural proteins, enabling a wide range of applications. Approaches such as rational design and directed evolution are routinely used to make new protein variants. Computational tools like de novo design can introduce new protein folds. Expanding the amino acid repertoire to include unnatural amino acids with non-canonical side chains in vitro by native chemical ligation and in vivo via codon expansion methods broadens sequence and structural possibilities. Circular permutation (CP) is an invaluable approach to redesigning a protein by rearranging the amino acid sequence, where the connectivity of the secondary structural elements is altered without changing the overall structure of the protein. Artificial CP proteins (CPs) are employed in various applications such as biocatalysis, sensing of small molecules by fluorescence, genome editing, ligand-binding protein switches, and optogenetic engineering. Many studies have shown that CP can lead to either reduced or enhanced stability or catalytic efficiency. The effects of CP on a protein's energy landscape cannot be predicted a priori. Thus, it is important to understand how CP can affect the thermodynamic and kinetic stability of a protein. In this review, we discuss the discovery and advancement of techniques to create protein CP, and existing reviews on CP. We delve into the plethora of biological applications for designed CP proteins. We subsequently discuss the experimental and computational reports on the effects of CP on the thermodynamic and kinetic stabilities of proteins of various topologies. An understanding of the various aspects of CP will allow the reader to design robust CP proteins for their specific purposes.
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Affiliation(s)
- Debanjana Das
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Mumbai, India
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Anderson NT, Xie JS, Chacko AN, Liu VL, Fan KC, Mukherjee A. Rational Design of a Circularly Permuted Flavin-Based Fluorescent Protein. Chembiochem 2024; 25:e202300814. [PMID: 38356332 PMCID: PMC11065581 DOI: 10.1002/cbic.202300814] [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: 12/01/2023] [Revised: 02/12/2024] [Accepted: 02/14/2024] [Indexed: 02/16/2024]
Abstract
Flavin-based fluorescent proteins are oxygen-independent reporters that hold great promise for imaging anaerobic and hypoxic biological systems. In this study, we explored the feasibility of applying circular permutation, a valuable method for the creation of fluorescent sensors, to flavin-based fluorescent proteins. We used rational design and structural data to identify a suitable location for circular permutation in iLOV, a flavin-based reporter derived from A. thaliana. However, relocating the N- and C-termini to this position resulted in a significant reduction in fluorescence. This loss of fluorescence was reversible, however, by fusing dimerizing coiled coils at the new N- and C-termini to compensate for the increase in local chain entropy. Additionally, by inserting protease cleavage sites in circularly permuted iLOV, we developed two protease sensors and demonstrated their application in mammalian cells. In summary, our work establishes the first approach to engineer circularly permuted FbFPs optimized for high fluorescence and further showcases the utility of circularly permuted FbFPs to serve as a scaffold for sensor engineering.
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Affiliation(s)
| | - Jason S. Xie
- Department of Molecular, Cellular, and Developmental Biology
| | | | - Vannie L. Liu
- Department of Molecular, Cellular, and Developmental Biology
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Wang W. Protein-Based Tools for Studying Neuromodulation. ACS Chem Biol 2024; 19:788-797. [PMID: 38581649 PMCID: PMC11129172 DOI: 10.1021/acschembio.4c00037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/08/2024]
Abstract
Neuromodulators play crucial roles in regulating neuronal activity and affecting various aspects of brain functions, including learning, memory, cognitive functions, emotional states, and pain modulation. In this Account, we describe our group's efforts in designing sensors and tools for studying neuromodulation. Our lab focuses on developing new classes of integrators that can detect neuromodulators across the whole brain while leaving a mark for further imaging analysis at high spatial resolution. Our lab also designed chemical- and light-dependent protein switches for controlling peptide activity to potentially modulate the endogenous receptors of the neuromodulatory system in order to study the causal effects of selective neuronal pathways.
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Affiliation(s)
- Wenjing Wang
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, 48109, USA
- Department of Chemistry, University of Michigan, Ann Arbor, MI, 48109, USA
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Das D, Ainavarapu SRK. Circular permutation at azurin's active site slows down its folding. J Biol Inorg Chem 2023; 28:737-749. [PMID: 37957357 DOI: 10.1007/s00775-023-02023-z] [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: 05/08/2023] [Accepted: 09/26/2023] [Indexed: 11/15/2023]
Abstract
Circular permutation (CP) is a technique by which the primary sequence of a protein is rearranged to create new termini. The connectivity of the protein is altered but the overall protein structure generally remains unperturbed. Understanding the effect of CP can help design robust proteins for numerous applications such as in genetic engineering, optoelectronics, and improving catalytic activity. Studies on different protein topologies showed that CP usually affects protein stability as well as unfolding rates. Though a significant number of proteins contain metals or other cofactors, reports of metalloprotein CPs are rare. Thus, we chose a bacterial metalloprotein, azurin, and its CP within the metal-binding site (cpF114). We studied the stabilities, folding, and unfolding rates of apo- and Zn2+-bound CP azurin using fluorescence and circular dichroism. The introduced CP had destabilizing effects on the protein. Also, the folding of the Zn2+-CP protein was much slower than that of the Zn2+-WT or apo-protein. We compared this study to our previously reported azurin-cpN42, where we had observed an equilibrium and kinetic intermediate. cpF114 exhibits an apparent two-state equilibrium unfolding but has an off-pathway kinetic intermediate. Our study hinted at CP as a method to modify the energy landscape of proteins to alter their folding pathways. WT azurin, being a faster folder, may have evolved to optimize the folding rate of metal-bound protein compared to its CPs, albeit all of them have the same structure and function. Our study underscores that protein sequence and protein termini positions are crucial for metalloproteins. TOC Figure. (Top) Zn2+-azurin WT structure (PDB code: 1E67) and 2-D topology diagram of Zn2+-cpF114 azurin. (Bottom) Cartoon diagram representing folding (red arrows) and unfolding (blue arrows) of apo- and Zn2+- WT and cpF114 azurins. The width of the arrows represents the rate of the corresponding processes.
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Affiliation(s)
- Debanjana Das
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Dr. Homi Bhabha Road, Colaba, Mumbai, 400005, India
| | - Sri Rama Koti Ainavarapu
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Dr. Homi Bhabha Road, Colaba, Mumbai, 400005, India.
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Alapin JM, Mohamed MS, Shrestha P, Khaled HG, Vorabyeva AG, Bowling HL, Oliveira MM, Klann E. Opto4E-BP, an optogenetic tool for inducible, reversible, and cell type-specific inhibition of translation initiation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.30.554643. [PMID: 37693507 PMCID: PMC10491233 DOI: 10.1101/2023.08.30.554643] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/12/2023]
Abstract
The protein kinase mechanistic target of rapamycin complex 1 (mTORC1) is one of the primary triggers for initiating cap-dependent translation. Amongst its functions, mTORC1 phosphorylates eIF4E-binding proteins (4E-BPs), which prevents them from binding to eIF4E and thereby enables translation initiation. mTORC1 signaling is required for multiple forms of protein synthesis-dependent synaptic plasticity and various forms of long-term memory (LTM), including associative threat memory. However, the approaches used thus far to target mTORC1 and its effectors, such as pharmacological inhibitors or genetic knockouts, lack fine spatial and temporal control. The development of a conditional and inducible eIF4E knockdown mouse line partially solved the issue of spatial control, but still lacked optimal temporal control to study memory consolidation. Here, we have designed a novel optogenetic tool (Opto4E-BP) for cell type-specific, light-dependent regulation of eIF4E in the brain. We show that light-activation of Opto4E-BP decreases protein synthesis in HEK cells and primary mouse neurons. In situ , light-activation of Opto4E-BP in excitatory neurons decreased protein synthesis in acute amygdala slices. Finally, light activation of Opto4E-BP in principal excitatory neurons in the lateral amygdala (LA) of mice after training blocked the consolidation of LTM. The development of this novel optogenetic tool to modulate eIF4E-dependent translation with spatiotemporal precision will permit future studies to unravel the complex relationship between protein synthesis and the consolidation of LTM.
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Nagasawa Y, Ueda HH, Kawabata H, Murakoshi H. LOV2-based photoactivatable CaMKII and its application to single synapses: Local Optogenetics. Biophys Physicobiol 2023; 20:e200027. [PMID: 38496236 PMCID: PMC10941968 DOI: 10.2142/biophysico.bppb-v20.0027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Accepted: 06/02/2023] [Indexed: 03/19/2024] Open
Abstract
Optogenetic techniques offer a high spatiotemporal resolution to manipulate cellular activity. For instance, Channelrhodopsin-2 with global light illumination is the most widely used to control neuronal activity at the cellular level. However, the cellular scale is much larger than the diffraction limit of light (<1 μm) and does not fully exploit the features of the "high spatial resolution" of optogenetics. For instance, until recently, there were no optogenetic methods to induce synaptic plasticity at the level of single synapses. To address this, we developed an optogenetic tool named photoactivatable CaMKII (paCaMKII) by fusing a light-sensitive domain (LOV2) to CaMKIIα, which is a protein abundantly expressed in neurons of the cerebrum and hippocampus and essential for synaptic plasticity. Combining photoactivatable CaMKII with two-photon excitation, we successfully activated it in single spines, inducing synaptic plasticity (long-term potentiation) in hippocampal neurons. We refer to this method as "Local Optogenetics", which involves the local activation of molecules and measurement of cellular responses. In this review, we will discuss the characteristics of LOV2, the recent development of its derivatives, and the development and application of paCaMKII.
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Affiliation(s)
- Yutaro Nagasawa
- Supportive Center for Brain Research, National Institute for Physiological Sciences, Okazaki, Aichi 444-8585, Japan
- Department of Physiological Sciences, SOKENDAI (The Graduate University for Advanced Studies), Okazaki, Aichi 444-8585, Japan
| | - Hiromi H Ueda
- Supportive Center for Brain Research, National Institute for Physiological Sciences, Okazaki, Aichi 444-8585, Japan
- Department of Physiological Sciences, SOKENDAI (The Graduate University for Advanced Studies), Okazaki, Aichi 444-8585, Japan
| | - Haruka Kawabata
- Supportive Center for Brain Research, National Institute for Physiological Sciences, Okazaki, Aichi 444-8585, Japan
- Department of Physiological Sciences, SOKENDAI (The Graduate University for Advanced Studies), Okazaki, Aichi 444-8585, Japan
| | - Hideji Murakoshi
- Supportive Center for Brain Research, National Institute for Physiological Sciences, Okazaki, Aichi 444-8585, Japan
- Department of Physiological Sciences, SOKENDAI (The Graduate University for Advanced Studies), Okazaki, Aichi 444-8585, Japan
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Shen J, Geng L, Li X, Emery C, Kroning K, Shingles G, Lee K, Heyden M, Li P, Wang W. A general method for chemogenetic control of peptide function. Nat Methods 2023; 20:112-122. [PMID: 36481965 PMCID: PMC10069916 DOI: 10.1038/s41592-022-01697-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2021] [Accepted: 10/21/2022] [Indexed: 12/13/2022]
Abstract
Natural or engineered peptides serve important biological functions. A general approach to achieve chemical-dependent activation of short peptides will be valuable for spatial and temporal control of cellular processes. Here we present a pair of chemically activated protein domains (CAPs) for controlling the accessibility of both the N- and C-terminal portion of a peptide. CAPs were developed through directed evolution of an FK506-binding protein. By fusing a peptide to one or both CAPs, the function of the peptide is blocked until a small molecule displaces them from the FK506-binding protein ligand-binding site. We demonstrate that CAPs are generally applicable to a range of short peptides, including a protease cleavage site, a dimerization-inducing heptapeptide, a nuclear localization signal peptide, and an opioid peptide, with a chemical dependence up to 156-fold. We show that the CAPs system can be utilized in cell cultures and multiple organs in living animals.
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Affiliation(s)
- Jiaqi Shen
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
- Department of Chemistry, University of Michigan, Ann Arbor, MI, USA
| | - Lequn Geng
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
- Department of Chemistry, University of Michigan, Ann Arbor, MI, USA
| | - Xingyu Li
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
- Department of Biologic and Materials Sciences & Prosthodontics, University of Michigan, Ann Arbor, MI, USA
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
| | - Catherine Emery
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
- Department of Biologic and Materials Sciences & Prosthodontics, University of Michigan, Ann Arbor, MI, USA
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI, USA
| | - Kayla Kroning
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
- Department of Chemistry, University of Michigan, Ann Arbor, MI, USA
| | - Gwendolyn Shingles
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
- Department of Chemistry, University of Michigan, Ann Arbor, MI, USA
| | - Kerry Lee
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA
| | - Matthias Heyden
- School of Molecular Sciences, Arizona State University, Tempe, AZ, USA
| | - Peng Li
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA.
- Department of Biologic and Materials Sciences & Prosthodontics, University of Michigan, Ann Arbor, MI, USA.
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA.
| | - Wenjing Wang
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA.
- Department of Chemistry, University of Michigan, Ann Arbor, MI, USA.
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McCue AC, Kuhlman B. Design and engineering of light-sensitive protein switches. Curr Opin Struct Biol 2022; 74:102377. [PMID: 35461160 PMCID: PMC9968517 DOI: 10.1016/j.sbi.2022.102377] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Revised: 03/18/2022] [Accepted: 03/20/2022] [Indexed: 11/03/2022]
Abstract
Engineered, light-sensitive protein switches are used to interrogate a broad variety of biological processes. These switches are typically constructed by genetically fusing naturally occurring light-responsive protein domains with functional domains from other proteins. Protein activity can be controlled using a variety of mechanisms including light-induced colocalization, caging, and allosteric regulation. Protein design efforts have focused on reducing background signaling, maximizing the change in activity upon light stimulation, and perturbing the kinetics of switching. It is common to combine structure-based modeling with experimental screening to identify ideal fusion points between domains and discover point mutations that optimize switching. Here, we introduce commonly used light-sensitive domains and summarize recent progress in using them to regulate protein activity.
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Affiliation(s)
- Amelia C McCue
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, NC, 27599, USA
| | - Brian Kuhlman
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, NC, 27599, USA; Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC, 27514, USA.
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Directed evolution approaches for optogenetic tool development. Biochem Soc Trans 2021; 49:2737-2748. [PMID: 34783342 DOI: 10.1042/bst20210700] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Revised: 10/16/2021] [Accepted: 10/21/2021] [Indexed: 12/30/2022]
Abstract
Photoswitchable proteins enable specific molecular events occurring in complex biological settings to be probed in a rapid and reversible fashion. Recent progress in the development of photoswitchable proteins as components of optogenetic tools has been greatly facilitated by directed evolution approaches in vitro, in bacteria, or in yeast. We review these developments and suggest future directions for this rapidly advancing field.
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