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Styles MJ, Boursier ME, McEwan MA, Santa EE, Mattmann ME, Slinger BL, Blackwell HE. Autoinducer-fluorophore conjugates enable FRET in LuxR proteins in vitro and in cells. Nat Chem Biol 2022; 18:1115-1124. [PMID: 35927585 PMCID: PMC9529866 DOI: 10.1038/s41589-022-01089-1] [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: 09/29/2021] [Accepted: 06/21/2022] [Indexed: 11/09/2022]
Abstract
Cell-to-cell signaling, or quorum sensing (QS), in many Gram-negative bacteria is governed by small molecule signals (N-acyl-L-homoserine lactones, AHLs) and their cognate receptors (LuxR-type proteins). The mechanistic underpinnings of QS in these bacteria are severely limited due to the challenges of isolating and manipulating most LuxR-type proteins. Reports of quantitative direct-binding experiments on LuxR-type proteins are scarce, and robust and generalizable methods that provide such data are largely nonexistent. We report herein a Förster resonance energy transfer (FRET) assay that leverages (1) conserved tryptophans located in the LuxR-type protein ligand-binding site and synthetic fluorophore-AHL conjugates, and (2) isolation of the proteins bound to weak agonists. The FRET assay permits straightforward measurement of ligand-binding affinities with receptor-either in vitro or in cells-and was shown to be compatible with six LuxR-type proteins. These methods will advance fundamental investigations of LuxR-type protein mechanism and the development of small molecule QS modulators.
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Affiliation(s)
- Matthew J Styles
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, USA
| | | | | | - Emma E Santa
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, USA
| | | | - Betty L Slinger
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, USA
| | - Helen E Blackwell
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, USA.
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2
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pruR and PA0065 Genes Are Responsible for Decreasing Antibiotic Tolerance by Autoinducer Analog-1 (AIA-1) in Pseudomonas aeruginosa. Antibiotics (Basel) 2022; 11:antibiotics11060773. [PMID: 35740179 PMCID: PMC9219673 DOI: 10.3390/antibiotics11060773] [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: 05/13/2022] [Revised: 05/30/2022] [Accepted: 06/03/2022] [Indexed: 11/17/2022] Open
Abstract
Pseudomonas aeruginosa infection is considered a high-risk nosocomial infection and is very difficult to eradicate because of its tolerance to antibiotic treatment. A new compound, autoinducer analog-1 (AIA-1), has been demonstrated to reduce antibiotic tolerance, but its mechanisms remain unknown. This study aimed to investigate the mechanisms of AIA-1 in the antibiotic tolerance of P. aeruginosa. A transposon mutant library was constructed using miniTn5pro, and screening was performed to isolate high tolerant mutants upon exposure to biapenem and AIA-1. We constructed a deletion mutant and complementation strain of the genes detected in transposon insertion site determination, pruR and PA0066-65-64, and performed killing assays with antibiotics and AIA-1. Gene expression upon exposure to biapenem and AIA-1 and their relationship to stress response genes were analyzed. High antibiotic tolerance was observed in Tn5-pruR and Tn5-PA0065 transposon mutants and their deletion mutants, ΔpruR and ΔPA0066-65-64. Complemented strains of pruR and PA0066-65-64 with their respective deletion mutants exhibited suppressed antibiotic tolerance. It was determined that deletion of PA0066-65-64 increased rpoS expression, and PA0066-65-64 affects antibiotic tolerance via the rpoS pathway. Additionally, antibiotics and AIA-1 were found to inhibit pruR and PA0066-65-64. This study proposed that pruR and PA0066-65-64 are members of the antibiotic tolerance suppressors.
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Ampomah-Wireko M, Luo C, Cao Y, Wang H, Nininahazwe L, Wu C. Chemical probe of AHL modulators on quorum sensing in Gram-Negative Bacteria and as antiproliferative agents: A review. Eur J Med Chem 2021; 226:113864. [PMID: 34626877 DOI: 10.1016/j.ejmech.2021.113864] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 09/17/2021] [Accepted: 09/19/2021] [Indexed: 11/16/2022]
Abstract
Pathogenic bacteria use an intercellular chemical communication system called quorum sensing (QS) to control the expression of cellular functions such as virulence factors, biofilm formation, toxin production, and antibiotic resistance in a manner that is highly dependent on population density. Hence, since the emergence of QS, there has been a great interest in exploiting the QS mechanism as a new drug target. Therefore, blocking the QS mechanism can be an effective strategy to control infection and solve the problem of drug resistance. So far, there is no clinically approved anti-QS drug that can disable the circuits of QS systems. This review discusses the quorum-sensing network systems and novel anti-QS inhibitors in some Gram-negative bacteria.
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Affiliation(s)
- Maxwell Ampomah-Wireko
- School of Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, 450001, PR China; Key Laboratory of Advanced Drug Preparation Technologies, Ministry of Education & School of Pharmaceutical Sciences, Zhengzhou, 450001, PR China; Zhengzhou Key Laboratory of New Veterinary Drug Preparation Innovation, Zhengzhou, 450001, PR China
| | - Chunying Luo
- School of Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, 450001, PR China; Key Laboratory of Advanced Drug Preparation Technologies, Ministry of Education & School of Pharmaceutical Sciences, Zhengzhou, 450001, PR China; Zhengzhou Key Laboratory of New Veterinary Drug Preparation Innovation, Zhengzhou, 450001, PR China
| | - Yaquan Cao
- School of Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, 450001, PR China; Key Laboratory of Advanced Drug Preparation Technologies, Ministry of Education & School of Pharmaceutical Sciences, Zhengzhou, 450001, PR China; Zhengzhou Key Laboratory of New Veterinary Drug Preparation Innovation, Zhengzhou, 450001, PR China
| | - Huanhuan Wang
- School of Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, 450001, PR China; Key Laboratory of Advanced Drug Preparation Technologies, Ministry of Education & School of Pharmaceutical Sciences, Zhengzhou, 450001, PR China; Zhengzhou Key Laboratory of New Veterinary Drug Preparation Innovation, Zhengzhou, 450001, PR China
| | - Lauraine Nininahazwe
- School of Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, 450001, PR China; Key Laboratory of Advanced Drug Preparation Technologies, Ministry of Education & School of Pharmaceutical Sciences, Zhengzhou, 450001, PR China; Zhengzhou Key Laboratory of New Veterinary Drug Preparation Innovation, Zhengzhou, 450001, PR China
| | - Chunli Wu
- School of Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, 450001, PR China; Key Laboratory of Advanced Drug Preparation Technologies, Ministry of Education & School of Pharmaceutical Sciences, Zhengzhou, 450001, PR China; Zhengzhou Key Laboratory of New Veterinary Drug Preparation Innovation, Zhengzhou, 450001, PR China.
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Vargas ELG, de Almeida FA, de Freitas LL, Pinto UM, Vanetti MCD. Plant compounds and nonsteroidal anti-inflammatory drugs interfere with quorum sensing in Chromobacterium violaceum. Arch Microbiol 2021; 203:5491-5507. [PMID: 34417652 DOI: 10.1007/s00203-021-02518-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Revised: 07/21/2021] [Accepted: 08/06/2021] [Indexed: 12/29/2022]
Abstract
Chromobacterium violaceum is a Gram-negative, saprophytic bacterium that can infect humans and its virulence may be regulated by quorum sensing via N-acyl homoserine lactones. A virtual screening study with plant compounds and nonsteroidal anti-inflammatory drugs for inhibition of C. violaceum quorum sensing system has been performed. In vitro evaluation was done to validate the in silico results. Molecular docking showed that phytol, margaric acid, palmitic acid, dipyrone, ketoprofen, and phenylbutazone bound to structures of CviR proteins of different C. violaceum strains. Phytol presented higher binding affinities than AHLs and furanones, recognized inducers, and inhibitors of quorum sensing, respectively. When tested in vitro, phytol at a non-inhibitory concentration was the most efficient tested compound to reduce phenotypes regulated by quorum sensing. The results indicate that in silico compound prospection to inhibit quorum sensing may be a good tool for finding alternative lead molecules.
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Affiliation(s)
| | - Felipe Alves de Almeida
- Department of Nutrition, Universidade Federal de Juiz de Fora (UFJF), 35.032-620, Governador Valadares, MG, Brazil
| | - Leonardo Luiz de Freitas
- Department of Microbiology, Universidade Federal de Viçosa (UFV), 36.570-900, Viçosa, MG, Brazil
| | - Uelinton Manoel Pinto
- Department of Food and Experimental Nutrition, Food Research Center, Universidade de São Paulo (USP), 05.508-900, São Paulo, SP, Brazil
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Chahande AM, Lathigara D, Prabhune AA, Devi RN. Red fluorescent ultra-small gold nanoclusters functionalized with signal molecules to probe specificity in quorum sensing receptors in gram-negative bacteria. Arch Microbiol 2021; 203:4293-4301. [PMID: 34109439 DOI: 10.1007/s00203-021-02338-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 04/13/2021] [Accepted: 04/17/2021] [Indexed: 02/03/2023]
Abstract
Ultra-small (size < 2 nm) gold nanoclusters (AuNCs) are used as fluorescent probes which have excellent applications in bioimaging and sensing due to their emission in visible and NIR spectral region. Here, this property is exploited for understanding the quorum sensing phenomenon in bacteria which is regulated by signal molecules which are specific to various species. AuNCs are then functionalized with the signal molecules, Acyl Homoserine Lactones (AHL) of varying carbon chain length, C-6, C-8, and C-12 without 3rd C modification, to sense different strains of gram-negative bacteria i.e., Escherichia coli, Cronobacter sakazakii and Pseudomonas aeruginosa. In the concentration employed, selectivity to a limited extent is observed between the three Gram-negative bacteria tested. E. coli showed emission with all the AHL conjugates and P. aeruginosa did not interact with any of the three conjugates, whereas C. sakazakii showed specificity to C-8AHL. This is probably due to selectivity for cognate AHL molecules of appropriate concentrations.
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Affiliation(s)
- Anurag M Chahande
- Catalysis and Inorganic Chemistry Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune, 411008, India
- Academy of Scientific and Innovative Research (AcSIR), Kamla Nehru Nagar, Ghaziabad, 201002, India
| | - Disha Lathigara
- Biochemical Science Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune, 411008, India
| | - Asmita A Prabhune
- Biochemical Science Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune, 411008, India.
| | - R Nandini Devi
- Catalysis and Inorganic Chemistry Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune, 411008, India.
- Academy of Scientific and Innovative Research (AcSIR), Kamla Nehru Nagar, Ghaziabad, 201002, India.
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Ali AI, O'Donnell MJ, Scott WL, Samaritoni JG. A solid-phase synthetic route to N-acylated α-alkyl-d,l-homoserine lactones. Tetrahedron Lett 2020. [DOI: 10.1016/j.tetlet.2020.152328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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7
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Shin D, Gorgulla C, Boursier ME, Rexrode N, Brown EC, Arthanari H, Blackwell HE, Nagarajan R. N-Acyl Homoserine Lactone Analog Modulators of the Pseudomonas aeruginosa Rhll Quorum Sensing Signal Synthase. ACS Chem Biol 2019; 14:2305-2314. [PMID: 31545595 DOI: 10.1021/acschembio.9b00671] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Virulence in the Gram-negative pathogen Pseudomonas aeruginosa relies in part on the efficient functioning of two LuxI/R dependent quorum sensing (QS) cascades, namely, the LasI/R and RhlI/R systems that generate and respond to N-(3-oxo)-dodecanoyl-l-homoserine lactone and N-butyryl-l-homoserine lactone, respectively. The two acyl homoserine lactone (AHL) synthases, LasI and RhlI, use 3-oxododecanoyl-ACP and butyryl-ACP, respectively, as the acyl-substrates to generate the corresponding autoinducer signals for the bacterium. Although AHL synthases represent excellent targets for developing QS modulators in P. aeruginosa, and in other related bacteria, the identification of potent and signal synthase specific inhibitors has represented a significant technical challenge. In the current study, we sought to test the utility of AHL analogs as potential modulators of an AHL synthase and selected RhlI in P. aeruginosa as an initial target. We systematically varied the chemical functionalities of the AHL headgroup, acyl chain tail, and head-to-tail linkage to construct a small library of signal analogs and evaluated them for RhlI modulatory activity. Although the native N-butyryl-l-homoserine lactone did not inhibit RhlI, we discovered that several of our long-chain, unsubstituted acyl-d-homoserine lactones and acyl-d-homocysteine thiolactones inhibited while a few of the 3-oxoacyl-chain counterparts activated the enzyme. Additional mechanistic investigations with acyl-substrate analogs and docking experiments with AHL analogs revealed two distinct inhibitor and activator binding pockets in the enzyme. This study provides the first evidence of the yet untapped potential of AHL analogs as signal synthase modulators of QS pathways.
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Affiliation(s)
- Daniel Shin
- Department of Chemistry and Biochemistry, Boise State University, 1910 University Dr., Boise, Idaho 83725, United States
| | - Christoph Gorgulla
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 240 Longwood Ave, Boston, Massachusetts 02115, United States
- Department of Physics, Harvard University, 17 Oxford Street, Cambridge, Massachusetts 02138, United States
| | - Michelle E. Boursier
- Department of Chemistry, University of Wisconsin—Madison, 1101 University Ave, Madison, Wisconsin 53706, United States
| | - Neilson Rexrode
- Department of Chemistry and Biochemistry, Boise State University, 1910 University Dr., Boise, Idaho 83725, United States
| | - Eric C. Brown
- Department of Chemistry and Biochemistry, Boise State University, 1910 University Dr., Boise, Idaho 83725, United States
| | - Haribabu Arthanari
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 240 Longwood Ave, Boston, Massachusetts 02115, United States
- Department of Cancer Biology, Dana Farber Cancer Institute, Boston, Massachusetts 02115, United States
| | - Helen E. Blackwell
- Department of Chemistry, University of Wisconsin—Madison, 1101 University Ave, Madison, Wisconsin 53706, United States
| | - Rajesh Nagarajan
- Department of Chemistry and Biochemistry, Boise State University, 1910 University Dr., Boise, Idaho 83725, United States
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Hansen MJ, Hille JI, Szymanski W, Driessen AJ, Feringa BL. Easily Accessible, Highly Potent, Photocontrolled Modulators of Bacterial Communication. Chem 2019. [DOI: 10.1016/j.chempr.2019.03.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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9
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Wellington S, Greenberg EP. Quorum Sensing Signal Selectivity and the Potential for Interspecies Cross Talk. mBio 2019; 10:e00146-19. [PMID: 30837333 PMCID: PMC6401477 DOI: 10.1128/mbio.00146-19] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Accepted: 01/24/2019] [Indexed: 01/03/2023] Open
Abstract
Many species of proteobacteria communicate with kin and coordinate group behaviors through a form of cell-cell signaling called acyl-homoserine lactone (AHL) quorum sensing (QS). Most AHL receptors are thought to be specific for their cognate signal, ensuring that bacteria cooperate and share resources only with closely related kin cells. Although specificity is considered fundamental to QS, there are reports of "promiscuous" receptors that respond broadly to nonself signals. These promiscuous responses expand the function of QS systems to include interspecies interactions and have been implicated in both interspecies competition and cooperation. Because bacteria are frequently members of polymicrobial communities, AHL cross talk between species could have profound impacts. To better understand the prevalence of QS promiscuity, we measured the activity of seven QS receptors in their native host organisms. To facilitate comparison of our results to previous studies, we also measured receptor activity using heterologous expression in Escherichia coli We found that the standard E. coli methods consistently overestimate receptor promiscuity and sensitivity and that overexpression of the receptors is sufficient to account for the discrepancy between native and E. coli reporters. Additionally, receptor overexpression resulted in AHL-independent activity in Pseudomonas aeruginosa Using our activation data, we developed a quantitative score of receptor selectivity. We find that the receptors display a wide range of selectivity and that most receptors respond sensitively and strongly to at least one nonself signal, suggesting a broad potential for cross talk between QS systems.IMPORTANCE Specific recognition of cognate signals is considered fundamental to cell signaling circuits as it creates fidelity in the communication system. In bacterial quorum sensing (QS), receptor specificity ensures that bacteria cooperate only with kin. There are examples, however, of QS receptors that respond promiscuously to multiple signals. "Eavesdropping" by these promiscuous receptors can be beneficial in both interspecies competition and cooperation. Despite their potential significance, we know little about the prevalence of promiscuous QS receptors. Further, many studies rely on methods requiring receptor overexpression, which is known to increase apparent promiscuity. By systematically studying QS receptors in their natural parent strains, we find that the receptors display a wide range of selectivity and that there is potential for significant cross talk between QS systems. Our results provide a basis for hypotheses about the evolution and function of promiscuous signal receptors and for predictions about interspecies interactions in complex microbial communities.
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Affiliation(s)
- Samantha Wellington
- Department of Microbiology, University of Washington, Seattle, Washington, USA
| | - E Peter Greenberg
- Department of Microbiology, University of Washington, Seattle, Washington, USA
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Boursier ME, Moore JD, Heitman KM, Shepardson-Fungairino SP, Combs JB, Koenig LC, Shin D, Brown EC, Nagarajan R, Blackwell HE. Structure-Function Analyses of the N-Butanoyl l-Homoserine Lactone Quorum-Sensing Signal Define Features Critical to Activity in RhlR. ACS Chem Biol 2018; 13:2655-2662. [PMID: 30114353 DOI: 10.1021/acschembio.8b00577] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen that coordinates the production of many virulence phenotypes at high population density via quorum sensing (QS). The LuxR-type receptor RhlR plays an important role in the P. aeruginosa QS process, and there is considerable interest in the development of chemical approaches to modulate the activity of this protein. RhlR is activated by a simple, low molecular weight N-acyl l-homoserine lactone signal, N-butanoyll-homoserine lactone (BHL). Despite the emerging prominence of RhlR in QS pathways, there has been limited exploration of the chemical features of the BHL scaffold that are critical to its function. In the current study, we sought to systematically delineate the structure-activity relationships (SARs) driving BHL activity for the first time. A focused library of BHL analogues was designed, synthesized, and evaluated in cell-based reporter gene assays for RhlR agonism and antagonism. These investigations allowed us to define a series of SARs for BHL-type ligands and identify structural motifs critical for both activation and inhibition of the RhlR receptor. Notably, we identified agonists that have ∼10-fold higher potencies in RhlR relative to BHL, are highly selective for RhlR agonism over LasR, and are active in the P. aeruginosa background. These compounds and the SARs reported herein should pave a route toward new chemical strategies to study RhlR in P. aeruginosa.
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Affiliation(s)
- Michelle E. Boursier
- Department of Chemistry, University of Wisconsin—Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Joseph D. Moore
- Department of Chemistry, University of Wisconsin—Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Katherine M. Heitman
- Department of Chemistry, University of Wisconsin—Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Sally P. Shepardson-Fungairino
- Department of Chemistry, University of Wisconsin—Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Joshua B. Combs
- Department of Chemistry, University of Wisconsin—Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Lea C. Koenig
- Department of Chemistry, University of Wisconsin—Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Daniel Shin
- Department of Chemistry and Biochemistry, Boise State University, 1910 University Drive, Boise, Idaho 83725, United States
| | - Eric C. Brown
- Department of Chemistry and Biochemistry, Boise State University, 1910 University Drive, Boise, Idaho 83725, United States
| | - Rajesh Nagarajan
- Department of Chemistry and Biochemistry, Boise State University, 1910 University Drive, Boise, Idaho 83725, United States
| | - Helen E. Blackwell
- Department of Chemistry, University of Wisconsin—Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
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