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dos Santos Rodrigues FH, Delgado GG, Santana da Costa T, Tasic L. Applications of fluorescence spectroscopy in protein conformational changes and intermolecular contacts. BBA ADVANCES 2023; 3:100091. [PMID: 37207090 PMCID: PMC10189374 DOI: 10.1016/j.bbadva.2023.100091] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/21/2023] Open
Abstract
Emission fluorescence is one of the most versatile and powerful biophysical techniques used in several scientific subjects. It is extensively applied in the studies of proteins, their conformations, and intermolecular contacts, such as in protein-ligand and protein-protein interactions, allowing qualitative, quantitative, and structural data elucidation. This review, aimed to outline some of the most widely used fluorescence techniques in this area, illustrate their applications and display a few examples. At first, the data on the intrinsic fluorescence of proteins is disclosed, mainly on the tryptophan side chain. Predominantly, research to study protein conformational changes, protein interactions, and changes in intensities and shifts of the fluorescence emission maximums were discussed. Fluorescence anisotropy or fluorescence polarization is a measurement of the changing orientation of a molecule in space, concerning the time between the absorption and emission events. Absorption and emission indicate the spatial alignment of the molecule's dipoles relative to the electric vector of the electromagnetic wave of excitation and emitted light, respectively. In other words, if the fluorophore population is excited with vertically polarized light, the emitted light will retain some polarization based on how fast it rotates in solution. Therefore, fluorescence anisotropy can be successfully used in protein-protein interaction investigations. Then, green fluorescent proteins (GFPs), photo-transformable fluorescent proteins (FPs) such as photoswitchable and photoconvertible FPs, and those with Large Stokes Shift (LSS) are disclosed in more detail. FPs are potent tools for the study of biological systems. Their versatility and wide range of colours and properties allow many applications. Finally, the application of fluorescence in life sciences is exposed, especially the application of FPs in fluorescence microscopy techniques with super-resolution that enables precise in vivo photolabeling to monitor the movement and interactions of target proteins.
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Affiliation(s)
| | - Gonzalo Garcia Delgado
- Chemical Biology Laboratory, Institute of Chemistry, Organic Chemistry Department, University of Campinas, P. O. Box 6154, Campinas 13083-970, SP, Brazil
| | - Thyerre Santana da Costa
- Chemical Biology Laboratory, Institute of Chemistry, Organic Chemistry Department, University of Campinas, P. O. Box 6154, Campinas 13083-970, SP, Brazil
| | - Ljubica Tasic
- Chemical Biology Laboratory, Institute of Chemistry, Organic Chemistry Department, University of Campinas, P. O. Box 6154, Campinas 13083-970, SP, Brazil
- Corresponding author: Ljubica Tasic: IQ, UNICAMP, Rua Josué de Castro sn, 13083-970 Campinas, SP, Brazil
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Soon JW, Oohora K, Hayashi T. A disulphide bond-mediated hetero-dimer of a hemoprotein and a fluorescent protein exhibiting efficient energy transfer †. RSC Adv 2022; 12:28519-28524. [PMID: 36320522 PMCID: PMC9535469 DOI: 10.1039/d2ra05249k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2022] [Accepted: 09/22/2022] [Indexed: 11/07/2022] Open
Abstract
Artificial protein hetero-dimerization is one of the promising strategies to construct protein-based chemical tools. In this work, cytochrome b562, an electron transfer hemoprotein, and green fluorescent protein (GFP) mutants with cysteine residues added to their surfaces were conjugated via a pyridyl disulphide-based thiol–disulfide exchange reaction. The eight hetero-dimers, which have cysteine residues at different positions to form the disulphide bonds, were obtained and characterized by gel-electrophoresis, mass spectrometry and size exclusion chromatography. The fluorescence properties of the hetero-dimers were evaluated by fluorescence spectroscopy and fluorescence lifetime measurements. Efficient photoinduced energy transfer from the GFP chromophore to the heme cofactor was observed in each of the hetero-dimers. The energy transfer efficiency is strongly dependent on the cross-linking residues, reaching 96%. Furthermore, the estimated Förster distance and the structure-based maximum possible distances of the donor and acceptor suggest that one of the hetero-dimers has a rigid protein–protein structure with favourable properties for energy transfer. The disulphide bond-mediated protein hetero-dimerization is useful for screening functional protein systems towards further developments. Hetero-dimerization of a hemoprotein and green fluorescent protein via a thiol–disulphide exchange reaction is achieved. The heterodimer has suitable cross-linking points and displays efficient energy transfer.![]()
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Affiliation(s)
- Julian Wong Soon
- Department of Applied Chemistry, Graduate School of Engineering, Osaka UniversitySuita565-0871Japan
| | - Koji Oohora
- Department of Applied Chemistry, Graduate School of Engineering, Osaka UniversitySuita565-0871Japan
| | - Takashi Hayashi
- Department of Applied Chemistry, Graduate School of Engineering, Osaka UniversitySuita565-0871Japan
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Mariam J, Hoskere Ashoka A, Gaded V, Ali F, Malvi H, Das A, Anand R. Deciphering protein microenvironment by using a cysteine specific switch-ON fluorescent probe. Org Biomol Chem 2021; 19:5161-5168. [PMID: 34037063 DOI: 10.1039/d1ob00698c] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Fluorescent probes provide an unparalleled opportunity to visualize and quantify dynamic events. Here, we employ a medium-size, cysteine specific coumarin based switch-ON fluorescent probe 'L' to track protein unfolding profiles and accessibility of cysteine residues in proteins. It was established that 'L' is highly selective and exhibits no artifact due to interaction with other bystander species. 'L' is able to gauge subtle changes in protein microenvironment and proved to be effective in delineating early unfolding events that are difficult to otherwise discern by classic techniques such as circular dichroism. By solving the X-ray structure of TadA and probing the temperature dependent fluorescence-ON response with native TadA and its cysteine mutants, it was revealed that unfolding occurs in a stage-wise manner and the regions that are functionally important form compact sub-domains and unfold at later stages. Our results assert that probe 'L' serves as an efficient tool to monitor subtle changes in protein structure and can be employed as a generic dye to study processes such as protein unfolding.
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Affiliation(s)
- Jessy Mariam
- Department of Chemistry, IIT Bombay, Mumbai-400076, India.
| | - Anila Hoskere Ashoka
- Analytical Science Discipline, CSIR-Central Salt and Marine Chemicals Research Institute, G.B. Marg, Bhavnagar: 364002, Gujarat, India
| | - Vandana Gaded
- Department of Chemistry, IIT Bombay, Mumbai-400076, India.
| | - Firoj Ali
- Analytical Science Discipline, CSIR-Central Salt and Marine Chemicals Research Institute, G.B. Marg, Bhavnagar: 364002, Gujarat, India
| | - Harshada Malvi
- Department of Chemistry, IIT Bombay, Mumbai-400076, India.
| | - Amitava Das
- Analytical Science Discipline, CSIR-Central Salt and Marine Chemicals Research Institute, G.B. Marg, Bhavnagar: 364002, Gujarat, India and Department of Chemical Sciences, Indian Institute of Science and Education Research, Kolkata, Mohanpur: 742246, India.
| | - Ruchi Anand
- Department of Chemistry, IIT Bombay, Mumbai-400076, India.
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Kaur A, Kaur P, Ahuja S. Förster resonance energy transfer (FRET) and applications thereof. ANALYTICAL METHODS : ADVANCING METHODS AND APPLICATIONS 2020; 12:5532-5550. [PMID: 33210685 DOI: 10.1039/d0ay01961e] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
FRET is a nonradiative process of energy transfer that is based on the dipole-dipole interactions between molecules that are fluorescent. Transfer of energy takes place rapidly from a donor molecule to an acceptor molecule in juxtaposition such as 0 to 10 nm without photonic radiation. FRET has occupied a center stage in biotechnology and biological studies. It is used to gain information on conformation changes in single molecules. The pharmaceutical industry has also developed large fluorescence detection systems with very small sample sizes, at the level of single molecules, using fluorescence correlation spectroscopy.
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Affiliation(s)
- Amrita Kaur
- Computer Science and Engineering Department, Thapar Institute of Engineering and Technology, Patiala, 147001, India
| | - Pardeep Kaur
- Department of Biotechnology, Sri Guru Granth Sahib World University, Fatehgarh Sahib, Punjab 140407, India.
| | - Sahil Ahuja
- Computer Science and Engineering Department, Thapar Institute of Engineering and Technology, Patiala, 147001, India
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Gleason PR, Kelly PI, Grisingher DW, Mills JH. An intrinsic FRET sensor of protein-ligand interactions. Org Biomol Chem 2020; 18:4079-4084. [PMID: 32427252 PMCID: PMC7313717 DOI: 10.1039/d0ob00793e] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We describe an approach for the development of fluorescent sensors of metabolite binding in which a genetically encoded fluorescent non-canonical amino acid (fNCAA) containing a 7-hydroxycoumarin moiety (7-HCAA) forms a FRET pair with native tryptophan residues. Although previous studies demonstrated the potential for using 7-HCAA as an acceptor for tryptophan, this approach has not yet been explored within a single protein containing multiple tryptophan residues. A structure-based analysis of a hexokinase enzyme with multiple native tryptophan residues identified glutamate 50 as a potential site of 7-HCAA incorporation; Glu50 moves closer to the native tryptophans upon substrate binding. Substitution of 7-HCAA at residue 50 led to an increase in FRET efficiency in the presence of the substrate; this effect was not observed in a control protein where no change in distance between 7-HCAA and the native tryptophans occurs on substrate binding. This system was then used to directly observe differences in binding affinity of the hexokinase that occur at a number of pH values. Our approach builds on previous research in that it eliminates the need for the incorporation of multiple fNCAAs or fluorescent labels within a target protein and can be used to study substrate binding with native ligands. As such, it serves to expand the versatility of FRET-based techniques.
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Affiliation(s)
- Patrick R Gleason
- School of Molecular Sciences and The Biodesign Center for Molecular Design and Biomimetics, Arizona State University, Tempe, AZ 85287, USA.
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Patel MJ, Biswas SB, Biswas-Fiss EE. Functional significance of the conserved C-Terminal VFVNFA motif in the retina-specific ABC transporter, ABCA4, and its role in inherited visual disease. Biochem Biophys Res Commun 2019; 519:46-52. [PMID: 31481235 DOI: 10.1016/j.bbrc.2019.08.121] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Accepted: 08/23/2019] [Indexed: 01/24/2023]
Abstract
The human retina-specific ATP binding cassette transporter, ABCA4, plays a significant role in the visual cycle. Mutations in the ABCA4 gene result in a broad spectrum of severe, blinding, retinal degenerative diseases, including Stargardt macular dystrophy, fundus flavimaculatus, autosomal recessive (ar)-retinitis pigmentosa, and ar-cone-rod dystrophy. Genetic testing frequently yields novel variants of unknown significance, making accurate prognosis and therapeutic approaches difficult. Recently, we have reported a novel variant of ABCA4 corresponding to a four-nucleotide deletion which led to a premature stop codon and loss of the last 161 amino acids, including the highly-conserved VFVNFA motif. Despite the presence of this motif among other ABCA proteins, knowledge of the functional significance of this sequence remains limited. In this study, we have conducted structural and functional analyses of recombinant ABCA4 polypeptides with altered VFVNFA motifs to evaluate the importance of this sequence. Further investigation of ABCA4 subdomain interactions, using Fluorescence Resonance Energy Transfer, demonstrated a loss of interaction between nucleotide binding domains in the absence of the VFVNFA motif.
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Affiliation(s)
- Meera J Patel
- Department of Medical and Molecular Sciences, University of Delaware, College of Health Sciences, Newark, DE 19716, USA.
| | - Subhasis B Biswas
- Department of Medical and Molecular Sciences, University of Delaware, College of Health Sciences, Newark, DE 19716, USA. %26
| | - Esther E Biswas-Fiss
- Department of Medical and Molecular Sciences, University of Delaware, College of Health Sciences, Newark, DE 19716, USA.
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