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Nguyen DT, Zhu L, Gray DL, Woods TJ, Padhi C, Flatt KM, Mitchell DA, van der Donk WA. Biosynthesis of Macrocyclic Peptides with C-Terminal β-Amino-α-keto Acid Groups by Three Different Metalloenzymes. ACS CENTRAL SCIENCE 2024; 10:1022-1032. [PMID: 38799663 PMCID: PMC11117315 DOI: 10.1021/acscentsci.4c00088] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Revised: 03/29/2024] [Accepted: 03/29/2024] [Indexed: 05/29/2024]
Abstract
Advances in genome sequencing and bioinformatics methods have identified a myriad of biosynthetic gene clusters (BGCs) encoding uncharacterized molecules. By mining genomes for BGCs containing a prevalent peptide-binding domain used for the biosynthesis of ribosomally synthesized and post-translationally modified peptides (RiPPs), we uncovered a new compound class involving modifications installed by a cytochrome P450, a multinuclear iron-dependent non-heme oxidative enzyme (MNIO, formerly DUF692), a cobalamin- and radical S-adenosyl-l-methionine-dependent enzyme (B12-rSAM), and a methyltransferase. All enzymes were functionally expressed in Burkholderia sp. FERM BP-3421. Structural characterization demonstrated that the P450 enzyme catalyzed the formation of a biaryl C-C cross-link between two Tyr residues with the B12-rSAM generating β-methyltyrosine. The MNIO transformed a C-terminal Asp residue into aminopyruvic acid, while the methyltransferase acted on the β-carbon of this α-keto acid. Exciton-coupled circular dichroism spectroscopy and microcrystal electron diffraction (MicroED) were used to elucidate the stereochemical configuration of the atropisomer formed upon biaryl cross-linking. To the best of our knowledge, the MNIO featured in this pathway is the first to modify a residue other than Cys. This study underscores the utility of genome mining to isolate new macrocyclic RiPPs biosynthesized via previously undiscovered enzyme chemistry.
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Affiliation(s)
- Dinh T. Nguyen
- Department
of Chemistry, Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Lingyang Zhu
- School
of Chemical Sciences NMR Laboratory, University
of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Danielle L. Gray
- School
of Chemical Sciences George L. Clark X-Ray Facility and 3M Materials
Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Toby J. Woods
- School
of Chemical Sciences George L. Clark X-Ray Facility and 3M Materials
Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Chandrashekhar Padhi
- Department
of Chemistry, Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Kristen M. Flatt
- Materials
Research Laboratory, University of Illinois
at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Douglas A. Mitchell
- Department
of Chemistry, Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Wilfred A. van der Donk
- Department
of Chemistry, Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
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2
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Krishnan SB, Clark RJ, Lin X, Dmitrenko O, Hilinski EF, Kuhn LR, Alabugin IV, Saltiel J. α-Methylstilbene Isomers: Relationship of Structure to Photophysics and Photochemistry. J Phys Chem A 2022; 126:8976-8987. [PMID: 36414392 DOI: 10.1021/acs.jpca.2c06319] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Significant differences in the photochemical and photophysical behavior of trans-α-methylstilbene and trans-stilbene have been attributed to structural changes caused by the steric requirements of the methyl group. We present here the X-ray structures of cis- and trans-α-methylstilbene (c- and t-MeSt). This is the first X-ray structure of a cis-stilbene. Despite the pronounced departure from phenyl group coplanarity, the solid-state packing of t-MeSt resembles that of trans-stilbene in that both exhibit disorder with a bicycle pedal structural relationship, dynamic in t-St but static in t-MeSt. We compare the X-ray structures with calculated structures. We also compare our steady state and transient photochemical and spectroscopic results with predictions in a recent theoretical paper that anticipated some of our experiments. Deviations from planarity imposed by the methyl substitution account for the shorter lifetimes of the trans excited states. The rapid torsional relaxation of 1t-MeSt* to the twisted intermediate 1p*, ktp = 2.9 × 1012 s-1, observed using fs transient absorption spectroscopy, explains the sharp decrease in the fluorescence quantum yield of t-MeSt. We correct misconceptions that have appeared in the literature concerning the shape of the stilbene potential energy surface in S1. The nonplanarity due to methyl substitution leads to chirality issues that are relevant in biological molecules such as the protonated Schiff bases of retinal in the opsins.
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Affiliation(s)
- Sumesh B Krishnan
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306-4390, United States
| | - Ronald J Clark
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306-4390, United States
| | - Xinsong Lin
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306-4390, United States
| | - Olga Dmitrenko
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States
| | - Edwin F Hilinski
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306-4390, United States
| | - Leah R Kuhn
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306-4390, United States
| | - Igor V Alabugin
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306-4390, United States
| | - Jack Saltiel
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306-4390, United States
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3
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Shim J, Choun K, Kang K, Kim J, Cho S, Jung K. The binding of secondary chromophore for thermally stable rhodopsin makes more stable with temperature. Protein Sci 2022. [DOI: 10.1002/pro.4386] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Jin‐gon Shim
- Department of Life Science and Institute of Biological Interfaces Sogang University Seoul South Korea
| | - Kimleng Choun
- Department of Life Science and Institute of Biological Interfaces Sogang University Seoul South Korea
| | - Kun‐Wook Kang
- Department of Life Science and Institute of Biological Interfaces Sogang University Seoul South Korea
| | - Ji‐Hyun Kim
- Department of Life Science and Institute of Biological Interfaces Sogang University Seoul South Korea
| | - Shin‐Gyu Cho
- Department of Life Science and Institute of Biological Interfaces Sogang University Seoul South Korea
| | - Kwang‐Hwan Jung
- Department of Life Science and Institute of Biological Interfaces Sogang University Seoul South Korea
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4
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de Grip WJ, Ganapathy S. Rhodopsins: An Excitingly Versatile Protein Species for Research, Development and Creative Engineering. Front Chem 2022; 10:879609. [PMID: 35815212 PMCID: PMC9257189 DOI: 10.3389/fchem.2022.879609] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2022] [Accepted: 05/16/2022] [Indexed: 01/17/2023] Open
Abstract
The first member and eponym of the rhodopsin family was identified in the 1930s as the visual pigment of the rod photoreceptor cell in the animal retina. It was found to be a membrane protein, owing its photosensitivity to the presence of a covalently bound chromophoric group. This group, derived from vitamin A, was appropriately dubbed retinal. In the 1970s a microbial counterpart of this species was discovered in an archaeon, being a membrane protein also harbouring retinal as a chromophore, and named bacteriorhodopsin. Since their discovery a photogenic panorama unfolded, where up to date new members and subspecies with a variety of light-driven functionality have been added to this family. The animal branch, meanwhile categorized as type-2 rhodopsins, turned out to form a large subclass in the superfamily of G protein-coupled receptors and are essential to multiple elements of light-dependent animal sensory physiology. The microbial branch, the type-1 rhodopsins, largely function as light-driven ion pumps or channels, but also contain sensory-active and enzyme-sustaining subspecies. In this review we will follow the development of this exciting membrane protein panorama in a representative number of highlights and will present a prospect of their extraordinary future potential.
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Affiliation(s)
- Willem J. de Grip
- Leiden Institute of Chemistry, Department of Biophysical Organic Chemistry, Leiden University, Leiden, Netherlands
- Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, Netherlands
| | - Srividya Ganapathy
- Department of Imaging Physics, Delft University of Technology, Netherlands
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5
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The role of carotenoids in proton-pumping rhodopsin as a primitive solar energy conversion system. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2021; 221:112241. [PMID: 34130090 DOI: 10.1016/j.jphotobiol.2021.112241] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Revised: 06/02/2021] [Accepted: 06/06/2021] [Indexed: 12/24/2022]
Abstract
Rhodopsin and carotenoids are two molecules that certain bacteria use to absorb and utilize light. Type I rhodopsin, the simplest active proton transporter, converts light energy into an electrochemical potential. Light produces a proton gradient, which is known as the proton motive force across the cell membrane. Some carotenoids are involved in light absorbance and transfer of absorbed energy to chlorophyll during photosynthesis. A previous study in Salinibacter ruber has shown that carotenoids act as antennae to harvest light and transfer energy to retinal in xanthorhodopsin (XR). Here, we describe the role of canthaxanthin (CAN), a carotenoid, as an antenna for Gloeobacter rhodopsin (GR). The non-covalent complex formed by the interaction between CAN and GR doubled the proton pumping speed and improved the pumping capacity by 1.5-fold. The complex also tripled the proton pumping speed and improved the pumping capacity by 5-fold in the presence of strong and weak light, respectively. Interestingly, when canthaxanthin was bound to Gloeobacter rhodopsin, it showed a 126-fold increase in heat resistance, and it survived better under drought conditions than Gloeobacter rhodopsin. The results suggest direct complementation of Gloeobacter rhodopsin with a carotenoid for primitive solar energy harvesting in cyanobacteria.
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Tutol JN, Lee J, Chi H, Faizuddin FN, Abeyrathna SS, Zhou Q, Morcos F, Meloni G, Dodani SC. A single point mutation converts a proton-pumping rhodopsin into a red-shifted, turn-on fluorescent sensor for chloride. Chem Sci 2021; 12:5655-5663. [PMID: 34163777 PMCID: PMC8179538 DOI: 10.1039/d0sc06061e] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Accepted: 03/08/2021] [Indexed: 12/11/2022] Open
Abstract
The visualization of chloride in living cells with fluorescent sensors is linked to our ability to design hosts that can overcome the energetic penalty of desolvation to bind chloride in water. Fluorescent proteins can be used as biological supramolecular hosts to address this fundamental challenge. Here, we showcase the power of protein engineering to convert the fluorescent proton-pumping rhodopsin GR from Gloeobacter violaceus into GR1, a red-shifted, turn-on fluorescent sensor for chloride in detergent micelles and in live Escherichia coli. This non-natural function was unlocked by mutating D121, which serves as the counterion to the protonated retinylidene Schiff base chromophore. Substitution from aspartate to valine at this position (D121V) creates a binding site for chloride. The binding of chloride tunes the pK a of the chromophore towards the protonated, fluorescent state to generate a pH-dependent response. Moreover, ion pumping assays combined with bulk fluorescence and single-cell fluorescence microscopy experiments with E. coli, expressing a GR1 fusion with a cyan fluorescent protein, show that GR1 does not pump ions nor sense membrane potential but instead provides a reversible, ratiometric readout of changes in extracellular chloride at the membrane. This discovery sets the stage to use natural and laboratory-guided evolution to build a family of rhodopsin-based fluorescent chloride sensors with improved properties for cellular applications and learn how proteins can evolve and adapt to bind anions in water.
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Affiliation(s)
- Jasmine N Tutol
- Department of Chemistry and Biochemistry, The University of Texas at Dallas Richardson TX 75080 USA
| | - Jessica Lee
- Department of Chemistry and Biochemistry, The University of Texas at Dallas Richardson TX 75080 USA
- Department of Biological Sciences, The University of Texas at Dallas Richardson TX 75080 USA
| | - Hsichuan Chi
- Department of Chemistry and Biochemistry, The University of Texas at Dallas Richardson TX 75080 USA
- Department of Biological Sciences, The University of Texas at Dallas Richardson TX 75080 USA
| | - Farah N Faizuddin
- Department of Chemistry and Biochemistry, The University of Texas at Dallas Richardson TX 75080 USA
- Department of Biological Sciences, The University of Texas at Dallas Richardson TX 75080 USA
| | - Sameera S Abeyrathna
- Department of Chemistry and Biochemistry, The University of Texas at Dallas Richardson TX 75080 USA
| | - Qin Zhou
- Department of Biological Sciences, The University of Texas at Dallas Richardson TX 75080 USA
| | - Faruck Morcos
- Department of Biological Sciences, The University of Texas at Dallas Richardson TX 75080 USA
- Department of Bioengineering, The University of Texas at Dallas Richardson TX 75080 USA
| | - Gabriele Meloni
- Department of Chemistry and Biochemistry, The University of Texas at Dallas Richardson TX 75080 USA
| | - Sheel C Dodani
- Department of Chemistry and Biochemistry, The University of Texas at Dallas Richardson TX 75080 USA
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