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Gong X, Brand CJ, Bertucci MA. Designing and synthesizing peptide-based quorum sensing modulators. Methods Enzymol 2024; 698:263-299. [PMID: 38886035 DOI: 10.1016/bs.mie.2024.04.017] [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: 06/20/2024]
Abstract
Quorum sensing (QS) is a density-dependent bacterial communication system that uses small molecules as regulatory modulators. Synthetic changes to these molecules can up-or-down-regulate this system, leading to control of phenotypes, like competence and virulence factor production, that have implications in human health. In this chapter, a methodology for library design and screening of synthetic autoinducing peptides (AIPs) to uncover QS SARs is delineated. Additionally, procedures for the synthesis, purification and analysis of linear and cyclic AIPs are detailed. This includes solutions for potential synthetic challenges including diketopiperazine formation when using N-methyl amino acids and cyclization of peptides containing N-terminal cysteine residues. These procedures have and are currently being applied to develop potent QS modulators in Streptococcus pneumoniae, Bacillus cereus, Streptococcus gordonii and Lactiplantibacillus plantarum.
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Affiliation(s)
- Xiaotian Gong
- Department of Chemistry, Lafayette College, Easton, PA, United States
| | - Carter J Brand
- Department of Chemistry, Lafayette College, Easton, PA, United States
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2
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Milly TA, Tal-Gan Y. Targeting Peptide-Based Quorum Sensing Systems for the Treatment of Gram-Positive Bacterial Infections. Pept Sci (Hoboken) 2023; 115:e24298. [PMID: 37397504 PMCID: PMC10312355 DOI: 10.1002/pep2.24298] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Accepted: 10/27/2022] [Indexed: 08/27/2023]
Abstract
Bacteria utilize a cell density-dependent communication system called quorum sensing (QS) to coordinate group behaviors. In Gram-positive bacteria, QS involves the production of and response to auto-inducing peptide (AIP) signaling molecules to modulate group phenotypes, including pathogenicity. As such, this bacterial communication system has been identified as a potential therapeutic target against bacterial infections. More specifically, developing synthetic modulators derived from the native peptide signal paves a new way to selectively block the pathogenic behaviors associated with this signaling system. Moreover, rational design and development of potent synthetic peptide modulators allows in depth understanding of the molecular mechanisms that drive QS circuits in diverse bacterial species. Overall, studies aimed at understanding the role of QS in microbial social behavior could result in the accumulation of significant knowledge of microbial interactions, and consequently lead to the development of alternative therapeutic agents to treat bacterial infectivity. In this review, we discuss recent advances in the development of peptide-based modulators to target QS systems in Gram-positive pathogens, with a focus on evaluating the therapeutic potential associated with these bacterial signaling pathways.
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Affiliation(s)
- Tahmina A. Milly
- Department of Chemistry, University of Nevada, Reno, 1664 North Virginia Street, Reno, Nevada, 89557, United States
| | - Yftah Tal-Gan
- Department of Chemistry, University of Nevada, Reno, 1664 North Virginia Street, Reno, Nevada, 89557, United States
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3
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Milly TA, Buttner AR, Rieth N, Hutnick E, Engler ER, Campanella AR, Lella M, Bertucci MA, Tal-Gan Y. Optimizing CSP1 Analogs for Modulating Quorum Sensing in Streptococcus pneumoniae with Bulky, Hydrophobic Nonproteogenic Amino Acid Substitutions. RSC Chem Biol 2022; 3:301-311. [PMID: 35359494 PMCID: PMC8905529 DOI: 10.1039/d1cb00224d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Accepted: 01/28/2022] [Indexed: 11/21/2022] Open
Abstract
The prompt appearance of multiantibiotic-resistant bacteria necessitates finding alternative treatments that can attenuate bacterial infections while minimizing the rate of antibiotic resistance development. Streptococcus pneumoniae, a notorious human pathogen, is responsible for severe antibiotic-resistant infections. Its pathogenicity is influenced by a cell-density communication system, termed quorum sensing (QS). As a result, controlling QS through the development of peptide-based QS modulators may serve to attenuate pneumococcal infections. Herein, we set out to evaluate the impact of the introduction of bulkier, nonproteogenic side-chain residues on the hydrophobic binding face of CSP1 to optimize receptor-binding interactions in both of the S. pneumoniae specificity groups. Our results indicate that these substitutions optimize the peptide–protein binding interactions, yielding several pneumococcal QS modulators with high potency. Moreover, pharmacological evaluation of lead analogs revealed that the incorporation of nonproteogenic amino acids increased the peptides’ half-life towards enzymatic degradation while remaining nontoxic. Overall, our data convey key considerations for SAR using nonproteogenic amino acids, which provide analogs with better pharmacological properties. The prompt appearance of multiantibiotic-resistant bacteria necessitates finding alternative treatments that can attenuate bacterial infections while minimizing the rate of antibiotic resistance development.![]()
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Affiliation(s)
- Tahmina A Milly
- Department of Chemistry, University of Nevada, Reno 1664 North Virginia Street Reno Nevada 89557 USA
| | - Alec R Buttner
- Department of Chemistry, Moravian University 1200 Main St. Bethlehem PA 18018 USA
| | - Naomi Rieth
- Department of Chemistry, Moravian University 1200 Main St. Bethlehem PA 18018 USA
| | - Elizabeth Hutnick
- Department of Chemistry, Moravian University 1200 Main St. Bethlehem PA 18018 USA
| | - Emilee R Engler
- Department of Chemistry, Moravian University 1200 Main St. Bethlehem PA 18018 USA
| | | | - Muralikrishna Lella
- Department of Chemistry, University of Nevada, Reno 1664 North Virginia Street Reno Nevada 89557 USA
| | - Michael A Bertucci
- Department of Chemistry, Lafayette College 701 Sullivan Rd. Easton PA 18042 USA
| | - Yftah Tal-Gan
- Department of Chemistry, University of Nevada, Reno 1664 North Virginia Street Reno Nevada 89557 USA
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4
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Lella M, Tal-Gan Y. Strategies to Attenuate the Competence Regulon in Streptococcus pneumoniae. Pept Sci (Hoboken) 2021; 113:e24222. [PMID: 34337308 PMCID: PMC8323945 DOI: 10.1002/pep2.24222] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Accepted: 01/19/2021] [Indexed: 12/18/2022]
Abstract
Streptococcus pneumoniae is an opportunistic respiratory human pathogen that poses a continuing threat to human health. Natural competence for genetic transformation in S. pneumoniae plays an important role in aiding pathogenicity and it is the best-characterized feature to acquire antimicrobial resistance genes by a frequent process of recombination. In S. pneumoniae, competence, along with virulence factor production, is controlled by a cell-density communication mechanism termed the competence regulon. In this review, we present the recent advances in the development of alternative methods to attenuate the pathogenicity of S. pneumoniae by targeting the various stages of the non-essential competence regulon communication system. We mainly focus on new developments related to competitively intercepting the competence regulon signaling through the introduction of promising dominant-negative Competence Stimulating Peptide (dnCSP) scaffolds. We also discuss recent reports on antibiotics that can block CSP export by disturbing the proton motive force (PMF) across the membrane and various ways to control the pneumococcal pathogenicity by activating the counter signaling circuit and targeting the pneumococcal proteome.
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Affiliation(s)
- Muralikrishna Lella
- Department of Chemistry, University of Nevada, Reno, 1664 North Virginia Street, Reno, NV 89557 (USA)
| | - Yftah Tal-Gan
- Department of Chemistry, University of Nevada, Reno, 1664 North Virginia Street, Reno, NV 89557 (USA)
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5
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Milly TA, Engler ER, Chichura KS, Buttner AR, Koirala B, Tal-Gan Y, Bertucci MA. Harnessing Multiple, Nonproteogenic Substitutions to Optimize CSP:ComD Hydrophobic Interactions in Group 1 Streptococcus pneumoniae. Chembiochem 2021; 22:1940-1947. [PMID: 33644965 DOI: 10.1002/cbic.202000876] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Revised: 02/27/2021] [Indexed: 11/12/2022]
Abstract
Streptococcus pneumoniae (pneumococcus) is a human pathobiont that causes drastic antibiotic-resistant infections and is responsible for millions of deaths universally. Pneumococcus pathogenicity relies on the competence-stimulating peptide (CSP)-mediated quorum-sensing (QS) pathway that controls competence development for genetic transformation and, consequently, the spread of antibiotic resistance and virulence genes. Modulation of QS in S. pneumoniae can therefore be used to enervate pneumococcal infectivity as well as minimize the susceptibility to resistance development. In this work, we sought to optimize the interaction of CSP1 with its cognate transmembrane histidine kinase receptor (ComD1) through substitution of proteogenic and nonproteogenic amino acids on the hydrophobic binding face of CSP1. The findings from this study not only provided additional structure-activity data that are significant in optimizing CSP1 potency, but also led to the development of potent QS modulators. These CSP-based QS modulators could be used as privileged scaffolds for the development of antimicrobial agents against pneumococcal infections.
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Affiliation(s)
- Tahmina A Milly
- Department of Chemistry, University of Nevada, Reno, 1664 North Virginia Street, Reno, NV 89557, USA
| | - Emilee R Engler
- Department of Chemistry, Moravian College, 1200 Main Street, Bethlehem, PA 18018, USA
| | - Kylie S Chichura
- Department of Chemistry, Moravian College, 1200 Main Street, Bethlehem, PA 18018, USA
| | - Alec R Buttner
- Department of Chemistry, Moravian College, 1200 Main Street, Bethlehem, PA 18018, USA
| | - Bimal Koirala
- Department of Chemistry, University of Nevada, Reno, 1664 North Virginia Street, Reno, NV 89557, USA
| | - Yftah Tal-Gan
- Department of Chemistry, University of Nevada, Reno, 1664 North Virginia Street, Reno, NV 89557, USA
| | - Michael A Bertucci
- Department of Chemistry, Moravian College, 1200 Main Street, Bethlehem, PA 18018, USA
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McBrayer DN, Cameron CD, Tal-Gan Y. Development and utilization of peptide-based quorum sensing modulators in Gram-positive bacteria. Org Biomol Chem 2020; 18:7273-7290. [PMID: 32914160 PMCID: PMC7530124 DOI: 10.1039/d0ob01421d] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Quorum sensing (QS) is a mechanism by which bacteria regulate cell density-dependent group behaviors. Gram-positive bacteria generally rely on auto-inducing peptide (AIP)-based QS signaling to regulate their group behaviors. To develop synthetic modulators of these behaviors, the natural peptide needs to be identified and its structure-activity relationships (SARs) with its cognate receptor (either membrane-bound or cytosolic) need to be understood. SAR information allows for the rational design of peptides or peptide mimics with enhanced characteristics, which in turn can be utilized in studies to understand species-specific QS mechanisms and as lead scaffolds for the development of therapeutic candidates that target QS. In this review, we discuss recent work associated with the approaches used towards forwarding each of these steps in Gram-positive bacteria, with a focus on species that have received less attention.
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Affiliation(s)
- Dominic N McBrayer
- Department of Chemistry, SUNY New Paltz, 1 Hawk Drive, New Paltz, NY 12561, USA. and Department of Chemistry, University of Nevada, Reno, 1664 N. Virginia Street, Reno, NV 89557, USA.
| | - Crissey D Cameron
- Department of Chemistry, University of Nevada, Reno, 1664 N. Virginia Street, Reno, NV 89557, USA.
| | - Yftah Tal-Gan
- Department of Chemistry, University of Nevada, Reno, 1664 N. Virginia Street, Reno, NV 89557, USA.
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Milly TA, Tal-Gan Y. Biological Evaluation of Native Streptococcal Competence Stimulating Peptides Reveal Potential Crosstalk Between Streptococcus mitis and Streptococcus pneumoniae and a New Scaffold for the Development of S. pneumoniae Quorum Sensing Modulators. RSC Chem Biol 2020; 1:60-67. [PMID: 32905481 PMCID: PMC7470514 DOI: 10.1039/d0cb00012d] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Streptococcus pneumoniae, an opportunistic human pathogen, acquires genes from its neighboring species of the mitis group of streptococci that confer antibiotic resistances and allow it to produce diverse virulence factors. Most species of the mitis group are naturally competent, and they utilize the competence stimulating peptide (CSP) and the CSP-dependent competence regulon, a conserved quorum sensing (QS) circuit, to regulate their competence behavior. The dependence of the mitis group on this communication pathway makes QS a potential target to control their behavior. In this work, we sought to evaluate the impact of native pheromones of the adjacent species of S. pneumoniae to modulate the activity of the S. pneumoniae competence regulon. Our results revealed the potential role of S. mitis as a modulator of QS in S. pneumoniae. Most importantly, our analysis also revealed that by using the native pheromone of S. mitis as a template, highly potent pan-group agonists and antagonists of the pneumococcal competence regulon could be developed. The newly developed QS modulators may have therapeutic utility in treating pneumococcus infections.
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Affiliation(s)
- Tahmina Ahmed Milly
- Department of Chemistry, University of Nevada, Reno, 1664 N. Virginia Street, Reno, Nevada 89557, United States
| | - Yftah Tal-Gan
- Department of Chemistry, University of Nevada, Reno, 1664 N. Virginia Street, Reno, Nevada 89557, United States
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Koirala B, Tal-Gan Y. Development of Streptococcus pneumoniae Pan-Group Quorum-Sensing Modulators. Chembiochem 2020; 21:340-345. [PMID: 31291510 PMCID: PMC6952583 DOI: 10.1002/cbic.201900365] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Indexed: 01/24/2023]
Abstract
The rapid increase in multidrug-resistant pathogens is a major health concern that could bring mankind back to the pre-antibiotic era. Streptococcus pneumoniae is a highly recombinogenic opportunistic pathogen that causes a variety of deadly diseases and rapidly develops resistance to current antibiotic treatments. S. pneumoniae pathogenicity is dependent on a cell-density communication mechanism, or quorum sensing (QS), termed the competence regulon. In this work, we set out to design signal-based QS modulators capable of affecting the two specificity groups found in S. pneumoniae. Through systematic analysis and rational design, we were able to construct peptide-based pan-group QS activators and inhibitors with activities in the nanomolar range. These novel analogues are privileged scaffolds for the development of anti-virulence therapeutics against S. pneumoniae infections.
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Affiliation(s)
- Bimal Koirala
- Department of Chemistry, University of Nevada, Reno, 1664 North Virginia Street, Reno, Nevada, 89557, United States
| | - Yftah Tal-Gan
- Department of Chemistry, University of Nevada, Reno, 1664 North Virginia Street, Reno, Nevada, 89557, United States
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9
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Koirala B, Phillips NR, Tal-Gan Y. Unveiling the Importance of Amide Protons in CSP:ComD Interactions in Streptococcus pneumoniae. ACS Med Chem Lett 2019; 10:880-886. [PMID: 31223442 DOI: 10.1021/acsmedchemlett.9b00038] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Accepted: 04/30/2019] [Indexed: 01/06/2023] Open
Abstract
Streptococcus pneumoniae is an opportunistic pathogen that can cause diseases ranging from mild respiratory infections to life-threatening conditions such as pneumonia, meningitis, and bacteremia. S. pneumoniae pathogenicity is dependent on the action of a 17-amino acid peptide pheromone, termed competence stimulating peptide (CSP) that controls the competence regulon, a quorum sensing (QS) circuit. Therefore, intercepting QS could have therapeutic implications in treating pneumococcal infections while avoiding emerging antimicrobial resistance. In this study, we set out to evaluate the impact of amide protons on CSP activity and metabolic stability through systematic N-methylation. Our results indicate that the majority of amide protons are critical for CSP activity, either through direct interactions with the cognate receptor or by stabilizing the bioactive conformation. Importantly, we identified several N-methyl CSP analogs, namely, CSP1(15)-N-Me-K6 and CSP1(15)-N-Me-F7, that retain their biological activity while exhibiting enhanced metabolic stability. These analogs are privileged scaffolds for the design of CSP-based QS modulators with drug-like properties.
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Affiliation(s)
- Bimal Koirala
- Department of Chemistry, University of Nevada, Reno, 1664 North Virginia Street, Reno, Nevada 89557, United States
| | - Naiya R. Phillips
- Department of Chemistry, University of Nevada, Reno, 1664 North Virginia Street, Reno, Nevada 89557, United States
| | - Yftah Tal-Gan
- Department of Chemistry, University of Nevada, Reno, 1664 North Virginia Street, Reno, Nevada 89557, United States
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Koirala B, Lin J, Lau GW, Tal-Gan Y. Development of a Dominant Negative Competence-Stimulating Peptide (dnCSP) that Attenuates Streptococcus pneumoniae Infectivity in a Mouse Model of Acute Pneumonia. Chembiochem 2018; 19:2380-2386. [PMID: 30211457 PMCID: PMC6251734 DOI: 10.1002/cbic.201800505] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Indexed: 01/08/2023]
Abstract
Streptococcus pneumoniae (pneumococcus) is a prevalent human pathogen responsible for a variety of diseases, including pneumonia, bacteremia, sepsis, meningitis and otitis media, with a death toll of >22 000 a year in the United States alone. Pneumococcus uses the competence regulon and its associated signaling peptide, the competence stimulating peptide (CSP), to initiate its attack on the host and establish an infection. In this work, we set out to: 1) develop a pan-group quorum sensing inhibitor that could effectively interact with both the pneumococcus ComD1 and ComD2 receptors; and 2) evaluate the utility of dominant-negative CSPs (dnCSPs) in attenuating pneumococcus infectivity. Our results highlight the potential of inhibiting the competence regulon as a therapeutic approach to combat pneumococcus infections.
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Affiliation(s)
- Bimal Koirala
- Department of Chemistry, University of Nevada, Reno, 1664 North Virginia Street, Reno, Nevada, 89557, United States
| | - Jingjun Lin
- Department of Pathobiology, University of Illinois at Urbana-Champaign, 2001 South Lincoln Avenue, Urbana, Illinois, 61802, United States
| | - Gee W. Lau
- Department of Pathobiology, University of Illinois at Urbana-Champaign, 2001 South Lincoln Avenue, Urbana, Illinois, 61802, United States
| | - Yftah Tal-Gan
- Department of Chemistry, University of Nevada, Reno, 1664 North Virginia Street, Reno, Nevada, 89557, United States
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Yang Y, Cornilescu G, Tal-Gan Y. Structural Characterization of Competence-Stimulating Peptide Analogues Reveals Key Features for ComD1 and ComD2 Receptor Binding in Streptococcus pneumoniae. Biochemistry 2018; 57:5359-5369. [PMID: 30125091 DOI: 10.1021/acs.biochem.8b00653] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Streptococcus pneumoniae is an important pathogen that utilizes quorum sensing (QS) to regulate genetic transformation, virulence, and biofilm formation. The competence-stimulating peptide (CSP) is a 17-amino acid signal peptide that is used by S. pneumoniae to trigger QS. S. pneumoniae strains can be divided into two main specificity groups based on the CSP signal they produce (CSP1 or CSP2) and their compatible receptors (ComD1 or ComD2, respectively). Modulation of QS in S. pneumoniae can be achieved by targeting the CSP:ComD interaction using synthetic CSP analogues. However, to rationally design CSP-based QS modulators with enhanced activities, an in-depth understanding of the structural features that are required for receptor binding is needed. Herein, we report a comprehensive in-solution three-dimensional structural characterization of eight CSP1 and CSP2 analogues with varied biological activities using nuclear magnetic resonance spectroscopy. Analysis of these structures revealed two distinct hydrophobic patches required for effective ComD1 and ComD2 binding.
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Affiliation(s)
- Yifang Yang
- Department of Chemistry , University of Nevada, Reno , 1664 North Virginia Street , Reno , Nevada 89557 , United States
| | - Gabriel Cornilescu
- National Magnetic Resonance Facility at Madison , University of Wisconsin-Madison , 433 Babcock Drive , Madison , Wisconsin 53706 , United States
| | - Yftah Tal-Gan
- Department of Chemistry , University of Nevada, Reno , 1664 North Virginia Street , Reno , Nevada 89557 , United States
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