1
|
Li F, Lan J, Li X, Chung LW. A Synergistic Bimetallic Ti/Co-Catalyzed Isomerization of Epoxides to Allylic Alcohols Enabled by Two-State Reactivity. Inorg Chem 2024; 63:6285-6295. [PMID: 38517250 DOI: 10.1021/acs.inorgchem.4c00011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/23/2024]
Abstract
Isomerization of epoxides into versatile allylic alcohols is an atom-economical synthetic method to afford vicinal bifunctional groups. Comprehensive density functional theory (DFT) calculations were carried out to elucidate the complex mechanism of a bimetallic Ti/Co-catalyzed selective isomerization of epoxides to allyl alcohols by examining several possible pathways. Our results suggest a possible mechanism involving (1) radical-type epoxide ring opening catalyzed by Cp2Ti(III)Cl leading to a Ti(IV)-bound β-alkyl radical, (2) hydrogen-atom transfer (HAT) catalyzed by the Co(II) catalyst to form the Ti(IV)-enolate and Co(III)-H intermediate, (3) protonation to give the alcohols, and (4) proton abstraction to form the Co(I) species followed by electron transfer to regenerate the active Co(II) and Ti(III) species. Moreover, bimetallic catalysis and two-state reactivity enable the key rate-determining HAT step. Furthermore, a subtle balance between dispersion-driven bimetallic processes and entropy-driven monometallic processes determines the most favorable pathway, among which the monometallic process is energetically more favorable in all steps except the vital hydrogen-atom transfer step. Our study should provide an in-depth mechanistic understanding of bimetallic catalysis.
Collapse
Affiliation(s)
- Fangfang Li
- Shenzhen Grubbs Institute and Department of Chemistry, Guangdong Provincial Key Laboratory of Catalysis, Southern University of Science and Technology, Shenzhen 518055, China
| | - Jialing Lan
- Shenzhen Grubbs Institute and Department of Chemistry, Guangdong Provincial Key Laboratory of Catalysis, Southern University of Science and Technology, Shenzhen 518055, China
| | - Xin Li
- Shenzhen Grubbs Institute and Department of Chemistry, Guangdong Provincial Key Laboratory of Catalysis, Southern University of Science and Technology, Shenzhen 518055, China
| | - Lung Wa Chung
- Shenzhen Grubbs Institute and Department of Chemistry, Guangdong Provincial Key Laboratory of Catalysis, Southern University of Science and Technology, Shenzhen 518055, China
| |
Collapse
|
2
|
Bhatti T, Kumar A, Parihar A, Moncy HK, Emge TJ, Waldie KM, Hasanayn F, Goldman AS. Metal-Ligand Proton Tautomerism, Electron Transfer, and C(sp 3)-H Activation by a 4-Pyridinyl-Pincer Iridium Hydride Complex. J Am Chem Soc 2023; 145:18296-18306. [PMID: 37552857 PMCID: PMC10450815 DOI: 10.1021/jacs.3c03376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Indexed: 08/10/2023]
Abstract
The para-N-pyridyl-based PCP pincer proligand 3,5-bis(di-tert-butylphosphinomethyl)-2,6-dimethylpyridine (pN-tBuPCP-H) was synthesized and metalated to give the iridium complex (pN-tBuPCP)IrHCl (2-H). In marked contrast with its phenyl-based congeners, e.g., (tBuPCP)IrHCl and derivatives, 2-H is highly air-sensitive and reacts with oxidants such as ferrocenium, trityl cation, and benzoquinone. These oxidations ultimately lead to intramolecular activation of a phosphino-t-butyl C(sp3)-H bond and cyclometalation. Considering the greater electronegativity of N than C, 2-H is expected to be less easily oxidized than simple PCP derivatives; cyclic voltammetry and DFT calculations support this expectation. However, 2-H is calculated to undergo metal-ligand-proton tautomerism (MLPT) to give an N-protonated complex that can be described with resonance forms representing a zwitterionic complex (with a negative charge on Ir) and a p-N-pyridylidene (a remote N-heterocyclic carbene) Ir(I) complex. One-electron oxidation of this tautomer is calculated to be dramatically more favorable than direct oxidation of 2-H (ΔΔG° = -31.3 kcal/mol). The resulting Ir(II) oxidation product is easily deprotonated to give metalloradical 2• which is observed by NMR spectroscopy. 2• can be further oxidized to give cationic Ir(III) complex, 2+, which can oxidatively add a phosphino-t-butyl C-H bond and undergo deprotonation to give the observed cyclometalated product. DFT calculations indicate that less sterically hindered analogues of 2+ would preferentially undergo intermolecular addition of C(sp3)-H bonds, for example, of n-alkanes. The resulting iridium alkyl complexes could undergo facile β-H elimination to afford olefin, thereby completing a catalytic cycle for alkane dehydrogenation driven by one-electron oxidation and deprotonation, enabled by MLPT.
Collapse
Affiliation(s)
- Tariq
M. Bhatti
- Department
of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, United States
| | - Akshai Kumar
- Centre
for Nanotechnology, Indian Institute of
Technology Guwahati, Guwahati 781039, Assam, India
| | - Ashish Parihar
- Department
of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, United States
| | - Hellan K. Moncy
- Department
of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, United States
| | - Thomas J. Emge
- Department
of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, United States
| | - Kate M. Waldie
- Department
of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, United States
| | - Faraj Hasanayn
- Department
of Chemistry, American University of Beirut, Beirut 1107 2020, Lebanon
| | - Alan S. Goldman
- Department
of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, United States
- Centre
for Nanotechnology, Indian Institute of
Technology Guwahati, Guwahati 781039, Assam, India
| |
Collapse
|
3
|
Chang X, Liu XT, Li F, Yang Y, Chung LW, Wang CJ. Electron-rich benzofulvenes as effective dipolarophiles in copper(i)-catalyzed asymmetric 1,3-dipolar cycloaddition of azomethine ylides. Chem Sci 2023; 14:5460-5469. [PMID: 37234882 PMCID: PMC10207880 DOI: 10.1039/d3sc00435j] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Accepted: 04/25/2023] [Indexed: 05/28/2023] Open
Abstract
A series of benzofulvenes without any electron-withdrawing substituents were employed as 2π-type dipolarophiles for the first time to participate in Cu(i)-catalyzed asymmetric 1,3-dipolar cycloaddition (1,3-DC) reactions of azomethine ylides. An intrinsic non-benzenoid aromatic characteristic from benzofulvenes serves as a key driving force for activation of the electron-rich benzofulvenes. Utilizing the current methodology, a wide range of multi-substituted chiral spiro-pyrrolidine derivatives containing two contiguous all-carbon quaternary centers were formed in good yield with exclusive chemo-/regioselectivity and high to excellent stereoselectivity. Computational mechanistic studies elucidate the origin of the stereochemical outcome and the chemoselectivity, in which the thermostability of these cycloaddition products is the major factor.
Collapse
Affiliation(s)
- Xin Chang
- Engineering Research Center of Organosilicon Compounds & Materials, Ministry of Education, College of Chemistry and Molecular Sciences, Wuhan University Wuhan 430072 China
- State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry Shanghai 230021 China
| | - Xue-Tao Liu
- Engineering Research Center of Organosilicon Compounds & Materials, Ministry of Education, College of Chemistry and Molecular Sciences, Wuhan University Wuhan 430072 China
- State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry Shanghai 230021 China
| | - Fangfang Li
- Department of Chemistry and Guangdong Provincial Key Laboratory of Catalysis, Southern University of Science and Technology Shenzhen 518055 China
| | - Yuhong Yang
- Department of Chemistry and Guangdong Provincial Key Laboratory of Catalysis, Southern University of Science and Technology Shenzhen 518055 China
| | - Lung Wa Chung
- Department of Chemistry and Guangdong Provincial Key Laboratory of Catalysis, Southern University of Science and Technology Shenzhen 518055 China
| | - Chun-Jiang Wang
- Engineering Research Center of Organosilicon Compounds & Materials, Ministry of Education, College of Chemistry and Molecular Sciences, Wuhan University Wuhan 430072 China
- State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry Shanghai 230021 China
| |
Collapse
|
4
|
Gatreddi S, Sui D, Hausinger RP, Hu J. Irreversible inactivation of lactate racemase by sodium borohydride reveals reactivity of the nickel-pincer nucleotide cofactor. ACS Catal 2023; 13:1441-1448. [PMID: 37886035 PMCID: PMC10599654 DOI: 10.1021/acscatal.2c05461] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The nickel-pincer nucleotide (NPN) cofactor discovered in lactate racemase from Lactiplantibacillus plantarum (LarALp) is essential for the activities of racemases/epimerases in the highly diverse LarA superfamily. Prior mechanistic studies have established a proton-coupled hydride-transfer mechanism for LarALp, but direct evidence showing that hydride attacks the C4 atom in the pyridinium ring of NPN has been lacking. Here, we show that sodium borohydride (NaBH4) irreversibly inactivates LarALp accompanied by a rapid color change of the enzyme. The altered ultraviolet-visible spectra during NaBH4 titration supported hydride transfer to C4 of NPN, and the concomitant Ni loss unraveled by mass spectrometry experiments accounted for the irreversible inactivation. High resolution structures of LarALp revealed a substantially weakened C-Ni bond in the metastable sulfite-NPN adduct where the NPN cofactor is in the reduced state. These findings allowed us to propose a mechanism of LarALp inactivation by NaBH4 that provides key insights into the enzyme-catalyzed reaction and sheds light on the reactivity of small molecule NPN mimetics.
Collapse
Affiliation(s)
- Santhosh Gatreddi
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, United States
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824, United States
| | - Dexin Sui
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, United States
| | - Robert P. Hausinger
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, United States
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824, United States
| | - Jian Hu
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, United States
- Department of Chemistry, Michigan State University, East Lansing, MI 48824, United States
| |
Collapse
|
5
|
Lan J, Zhang T, Yang Y, Li X, Chung LW. A Mechanistic Study of the Cobalt(I)-Catalyzed Amination of Aryl Halides: Effects of Metal and Ligand. Inorg Chem 2022; 61:18019-18032. [DOI: 10.1021/acs.inorgchem.2c02385] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Jialing Lan
- School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin, 150001, China
- Shenzhen Grubbs Institute, Department of Chemistry and Guangdong Provincial Key Laboratory of Catalysis, Southern University of Science and Technology (SUSTech), Shenzhen, 518055, China
| | - Tonghuan Zhang
- Shenzhen Grubbs Institute, Department of Chemistry and Guangdong Provincial Key Laboratory of Catalysis, Southern University of Science and Technology (SUSTech), Shenzhen, 518055, China
- Lab of Computational Chemistry and Drug Design, Key Laboratory of Chemical Genomics, Peking University Shenzhen Graduate School, Shenzhen, 518055, China
| | - Yuhong Yang
- Shenzhen Grubbs Institute, Department of Chemistry and Guangdong Provincial Key Laboratory of Catalysis, Southern University of Science and Technology (SUSTech), Shenzhen, 518055, China
| | - Xin Li
- Shenzhen Grubbs Institute, Department of Chemistry and Guangdong Provincial Key Laboratory of Catalysis, Southern University of Science and Technology (SUSTech), Shenzhen, 518055, China
| | - Lung Wa Chung
- Shenzhen Grubbs Institute, Department of Chemistry and Guangdong Provincial Key Laboratory of Catalysis, Southern University of Science and Technology (SUSTech), Shenzhen, 518055, China
| |
Collapse
|
6
|
Chatterjee S, Gatreddi S, Gupta S, Nevarez JL, Rankin JA, Turmo A, Hu J, Hausinger RP. Unveiling the mechanisms and biosynthesis of a novel nickel-pincer enzyme. Biochem Soc Trans 2022; 50:1187-1196. [PMID: 35960008 PMCID: PMC9880988 DOI: 10.1042/bst20220490] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 07/28/2022] [Accepted: 07/29/2022] [Indexed: 01/31/2023]
Abstract
The nickel-pincer nucleotide (NPN) coenzyme, a substituted pyridinium mononucleotide that tri-coordinates nickel, was first identified covalently attached to a lysine residue in the LarA protein of lactate racemase. Starting from nicotinic acid adenine dinucleotide, LarB carboxylates C5 of the pyridinium ring and hydrolyzes the phosphoanhydride, LarE converts the C3 and C5 carboxylates to thiocarboxylates, and LarC incorporates nickel to form a C-Ni and two S-Ni bonds, during the biosynthesis of this cofactor. LarB uses a novel carboxylation mechanism involving the transient formation of a cysteinyl-pyridinium adduct. Depending on the source of the enzyme, LarEs either catalyze a sacrificial sulfur transfer from a cysteinyl side chain resulting in the formation of dehydroalanine or they utilize a [4Fe-4S] cluster bound by three cysteine residues to accept and transfer a non-core sulfide atom. LarC is a CTP-dependent enzyme that cytidinylylates its substrate, adds nickel, then hydrolyzes the product to release NPN and CMP. Homologs of the four lar genes are widely distributed in microorganisms, with some species containing multiple copies of larA whereas others lack this gene, consistent with the cofactor serving other functions. Several LarA-like proteins were shown to catalyze racemase or epimerase activities using 2-hydroxyacid substrates other than lactic acid. Thus, lactate racemase is the founding member of a large family of NPN-containing enzymes.
Collapse
Affiliation(s)
- Shramana Chatterjee
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824, USA
| | - Santhosh Gatreddi
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824, USA
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA
| | - Swati Gupta
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824, USA
| | - Jorge L. Nevarez
- Department of Chemistry, Michigan State University, East Lansing, MI 48824, USA
| | - Joel A. Rankin
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824, USA
| | - Aiko Turmo
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA
| | - Jian Hu
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA
- Department of Chemistry, Michigan State University, East Lansing, MI 48824, USA
| | - Robert P. Hausinger
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824, USA
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA
| |
Collapse
|
7
|
Lan J, Li X, Yang Y, Zhang X, Chung LW. New Insights and Predictions into Complex Homogeneous Reactions Enabled by Computational Chemistry in Synergy with Experiments: Isotopes and Mechanisms. Acc Chem Res 2022; 55:1109-1123. [PMID: 35385649 DOI: 10.1021/acs.accounts.1c00774] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Homogeneous catalysis and biocatalysis have been widely applied in synthetic, medicinal, and energy chemistry as well as synthetic biology. Driven by developments of new computational chemistry methods and better computer hardware, computational chemistry has become an essentially indispensable mechanistic "instrument" to help understand structures and decipher reaction mechanisms in catalysis. In addition, synergy between computational and experimental chemistry deepens our mechanistic understanding, which further promotes the rational design of new catalysts. In this Account, we summarize new or deeper mechanistic insights (including isotope, dispersion, and dynamical effects) into several complex homogeneous reactions from our systematic computational studies along with subsequent experimental studies by different groups. Apart from uncovering new mechanisms in some reactions, a few computational predictions (such as excited-state heavy-atom tunneling, steric-controlled enantioswitching, and a new geminal addition mechanism) based on our mechanistic insights were further verified by ensuing experiments.The Zimmerman group developed a photoinduced triplet di-π-methane rearrangement to form cyclopropane derivatives. Recently, our computational study predicted the first excited-state heavy-atom (carbon) quantum tunneling in one triplet di-π-methane rearrangement, in which the reaction rates and 12C/13C kinetic isotope effects (KIEs) can be enhanced by quantum tunneling at low temperatures. This unprecedented excited-state heavy-atom tunneling in a photoinduced reaction has recently been verified by an experimental 12C/13C KIE study by the Singleton group. Such combined computational and experimental studies should open up opportunities to discover more rare excited-state heavy-atom tunneling in other photoinduced reactions. In addition, we found unexpectedly large secondary KIE values in the five-coordinate Fe(III)-catalyzed hetero-Diels-Alder pathway, even with substantial C-C bond formation, due to the non-negligible equilibrium isotope effect (EIE) derived from altered metal coordination. Therefore, these KIE values cannot reliably reflect transition-state structures for the five-coordinate metal pathway. Furthermore, our density functional theory (DFT) quasi-classical molecular dynamics (MD) simulations demonstrated that the coordination mode and/or spin state of the iron metal as well as an electric field can affect the dynamics of this reaction (e.g., the dynamically stepwise process, the entrance/exit reaction channels).Moreover, we unveiled a new reaction mechanism to account for the uncommon Ru(II)-catalyzed geminal-addition semihydrogenation and hydroboration of silyl alkynes. Our proposed key gem-Ru(II)-carbene intermediates derived from double migrations on the same alkyne carbon were verified by crossover experiments. Additionally, our DFT MD simulations suggested that the first hydrogen migration transition-state structures may directly and quickly form the key gem-Ru-carbene structures, thereby "bypassing" the second migration step. Furthermore, our extensive study revealed the origin of the enantioselectivity of the Cu(I)-catalyzed 1,3-dipolar cycloaddition of azomethine ylides with β-substituted alkenyl bicyclic heteroarenes enabled by dual coordination of both substrates. Such mechanistic insights promoted our computational predictions of the enantioselectivity reversal for the corresponding monocyclic heteroarene substrates and the regiospecific addition to the less reactive internal C═C bond of one diene substrate. These predictions were proven by our experimental collaborators. Finally, our mechanistic insights into a few other reactions are also presented. Overall, we hope that these interactive computational and experimental studies enrich our mechanistic understanding and aid in reaction development.
Collapse
Affiliation(s)
- Jialing Lan
- School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150001, China
- Shenzhen Grubbs Institute, Department of Chemistry, and Guangdong Provincial Key Laboratory of Catalysis, Southern University of Science and Technology (SUSTech), Shenzhen 518055, China
| | - Xin Li
- Shenzhen Grubbs Institute, Department of Chemistry, and Guangdong Provincial Key Laboratory of Catalysis, Southern University of Science and Technology (SUSTech), Shenzhen 518055, China
| | - Yuhong Yang
- Shenzhen Grubbs Institute, Department of Chemistry, and Guangdong Provincial Key Laboratory of Catalysis, Southern University of Science and Technology (SUSTech), Shenzhen 518055, China
| | - Xiaoyong Zhang
- Shenzhen Grubbs Institute, Department of Chemistry, and Guangdong Provincial Key Laboratory of Catalysis, Southern University of Science and Technology (SUSTech), Shenzhen 518055, China
| | - Lung Wa Chung
- Shenzhen Grubbs Institute, Department of Chemistry, and Guangdong Provincial Key Laboratory of Catalysis, Southern University of Science and Technology (SUSTech), Shenzhen 518055, China
| |
Collapse
|
8
|
Chang X, Yang Y, Shen C, Xue KS, Wang ZF, Cong H, Tao HY, Chung LW, Wang CJ. β-Substituted Alkenyl Heteroarenes as Dipolarophiles in the Cu(I)-Catalyzed Asymmetric 1,3-Dipolar Cycloaddition of Azomethine Ylides Empowered by a Dual Activation Strategy: Stereoselectivity and Mechanistic Insight. J Am Chem Soc 2021; 143:3519-3535. [DOI: 10.1021/jacs.0c12911] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Xin Chang
- College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, People’s Republic of China
- State Key Laboratory of of Elemento-organic Chemistry, Nankai University, Tianjin 300071, People’s Republic of China
| | - Yuhong Yang
- Shenzhen Grubbs Institute, Department of Chemistry and Guangdong Provincial Key Laboratory of Catalysis, Southern University of Science and Technology, Shenzhen 518055, People’s Republic of China
- School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150001, People’s Republic of China
| | - Chong Shen
- College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, People’s Republic of China
| | - Kun-Shan Xue
- College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, People’s Republic of China
| | - Zuo-Fei Wang
- College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, People’s Republic of China
| | - Hengjiang Cong
- College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, People’s Republic of China
| | - Hai-Yan Tao
- College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, People’s Republic of China
| | - Lung Wa Chung
- Shenzhen Grubbs Institute, Department of Chemistry and Guangdong Provincial Key Laboratory of Catalysis, Southern University of Science and Technology, Shenzhen 518055, People’s Republic of China
| | - Chun-Jiang Wang
- College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, People’s Republic of China
- State Key Laboratory of of Elemento-organic Chemistry, Nankai University, Tianjin 300071, People’s Republic of China
| |
Collapse
|
9
|
Abstract
At least two types of pincer complexes are known to exist in biology. A metal-pyrroloquinolone quinone (PQQ) cofactor was first identified in bacterial methanol dehydrogenase, and later also found in selected short-chain alcohol dehydrogenases of other microorganisms. The PQQ-associated metal can be calcium, magnesium, or a rare earth element depending on the enzyme sequence. Synthesis of this organic ligand requires a series of accessory proteins acting on a small peptide, PqqA. Binding of metal to PQQ yields an ONO-type pincer complex. More recently, a nickel-pincer nucleotide (NPN) cofactor was discovered in lactate racemase, LarA. This cofactor derives from nicotinic acid adenine dinucleotide via action of a carboxylase/hydrolase, sulfur transferase, and nickel insertase, resulting in an SCS-type pincer complex. The NPN cofactor likely occurs in selected other racemases and epimerases of bacteria, archaea, and a few eukaryotes.
Collapse
Affiliation(s)
- Jorge Nevarez
- Department of Chemistry, 578 South Shaw Lane, Michigan State University, East Lansing, Michigan 48824 (USA)
| | - Aiko Turmo
- Department of Biochemistry and Molecular Biology, 603 Wilson Road, Room 212, Michigan State University, East Lansing, Michigan 48824 (USA)
| | - Jian Hu
- Department of Chemistry, 578 South Shaw Lane, Michigan State University, East Lansing, Michigan 48824 (USA).,Department of Biochemistry and Molecular Biology, 603 Wilson Road, Room 212, Michigan State University, East Lansing, Michigan 48824 (USA)
| | - Robert P Hausinger
- Department of Biochemistry and Molecular Biology, 603 Wilson Road, Room 212, Michigan State University, East Lansing, Michigan 48824 (USA).,Department of Microbiology and Molecular Genetics, 567 Wilson Road, 2215 Biomedical Physical Sciences, Michigan State University, East Lansing, Michigan 48824 (USA)
| |
Collapse
|
10
|
Yang Y, Zhang X, Zhong LP, Lan J, Li X, Li CC, Chung LW. Unusual KIE and dynamics effects in the Fe-catalyzed hetero-Diels-Alder reaction of unactivated aldehydes and dienes. Nat Commun 2020; 11:1850. [PMID: 32296076 PMCID: PMC7160212 DOI: 10.1038/s41467-020-15599-w] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Accepted: 03/13/2020] [Indexed: 12/30/2022] Open
Abstract
Hetero-Diels-Alder (HDA) reaction is an important synthetic method for many natural products. An iron(III) catalyst was developed to catalyze the challenging HDA reaction of unactivated aldehydes and dienes with high selectivity. Here we report extensive density-functional theory (DFT) calculations and molecular dynamics simulations that show effects of iron (including its coordinate mode and/or spin state) on the dynamics of this reaction: considerably enhancing dynamically stepwise process, broadening entrance channel and narrowing exit channel from concerted asynchronous transition states. Also, our combined computational and experimental secondary KIE studies reveal unexpectedly large KIE values for the five-coordinate pathway even with considerable C-C bond forming, due to equilibrium isotope effect from the change in the metal coordination. Moreover, steric and electronic effects are computationally shown to dictate the C=O chemoselectivity for an α,β-unsaturated aldehyde, which is verified experimentally. Our mechanistic study may help design homogeneous, heterogeneous and biological catalysts for this challenging reaction.
Collapse
Affiliation(s)
- Yuhong Yang
- School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin, 150001, China
- Shenzhen Grubbs Institute, Department of Chemistry and Guangdong Provincial Key Laboratory of Catalytic Chemistry, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Xiaoyong Zhang
- Shenzhen Grubbs Institute, Department of Chemistry and Guangdong Provincial Key Laboratory of Catalytic Chemistry, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Li-Ping Zhong
- Shenzhen Grubbs Institute, Department of Chemistry and Guangdong Provincial Key Laboratory of Catalytic Chemistry, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Jialing Lan
- School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin, 150001, China
- Shenzhen Grubbs Institute, Department of Chemistry and Guangdong Provincial Key Laboratory of Catalytic Chemistry, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Xin Li
- Shenzhen Grubbs Institute, Department of Chemistry and Guangdong Provincial Key Laboratory of Catalytic Chemistry, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Chuang-Chuang Li
- Shenzhen Grubbs Institute, Department of Chemistry and Guangdong Provincial Key Laboratory of Catalytic Chemistry, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Lung Wa Chung
- Shenzhen Grubbs Institute, Department of Chemistry and Guangdong Provincial Key Laboratory of Catalytic Chemistry, Southern University of Science and Technology, Shenzhen, 518055, China.
| |
Collapse
|
11
|
Shi R, Wodrich MD, Pan H, Tirani FF, Hu X. Functional Models of the Nickel Pincer Nucleotide Cofactor of Lactate Racemase. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201910490] [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)
- Renyi Shi
- Laboratory of Inorganic Synthesis and CatalysisInstitute of Chemical Sciences and EngineeringÉcole Polytechnique Fédérale de Lausanne (EPFL), ISIC-LSCI BCH 3305 Lausanne 1015 Switzerland
| | - Matthew D. Wodrich
- Laboratory of Inorganic Synthesis and CatalysisInstitute of Chemical Sciences and EngineeringÉcole Polytechnique Fédérale de Lausanne (EPFL), ISIC-LSCI BCH 3305 Lausanne 1015 Switzerland
- Laboratory for Computational Molecular DesignInstitute of Chemical Science and EngineeringEcole Polytechnique Fédérale de Lausanne (EPFL) Lausanne 1015 Switzerland
| | - Hui‐Jie Pan
- Laboratory of Inorganic Synthesis and CatalysisInstitute of Chemical Sciences and EngineeringÉcole Polytechnique Fédérale de Lausanne (EPFL), ISIC-LSCI BCH 3305 Lausanne 1015 Switzerland
| | - Farzaneh Fadaei Tirani
- Laboratory of Inorganic Synthesis and CatalysisInstitute of Chemical Sciences and EngineeringÉcole Polytechnique Fédérale de Lausanne (EPFL), ISIC-LSCI BCH 3305 Lausanne 1015 Switzerland
| | - Xile Hu
- Laboratory of Inorganic Synthesis and CatalysisInstitute of Chemical Sciences and EngineeringÉcole Polytechnique Fédérale de Lausanne (EPFL), ISIC-LSCI BCH 3305 Lausanne 1015 Switzerland
| |
Collapse
|
12
|
Shi R, Wodrich MD, Pan HJ, Tirani FF, Hu X. Functional Models of the Nickel Pincer Nucleotide Cofactor of Lactate Racemase. Angew Chem Int Ed Engl 2019; 58:16869-16872. [PMID: 31535787 DOI: 10.1002/anie.201910490] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Indexed: 11/06/2022]
Abstract
A novel nickel pincer cofactor was recently discovered in lactate racemase. Reported here are three synthetic nickel pincer complexes that are both structural and functional models of the pincer cofactor in lactate racemase. DFT computations suggest the ipso-carbon atom of the pyridinium pincer ligands act as a hydride acceptor for lactate isomerization, whereas an organometallic pathway involving nickel-mediated β-hydride elimination is less favored.
Collapse
Affiliation(s)
- Renyi Shi
- Laboratory of Inorganic Synthesis and Catalysis, Institute of Chemical Sciences and Engineering, École Polytechnique Fédérale de Lausanne (EPFL), ISIC-LSCI, BCH 3305, Lausanne, 1015, Switzerland
| | - Matthew D Wodrich
- Laboratory of Inorganic Synthesis and Catalysis, Institute of Chemical Sciences and Engineering, École Polytechnique Fédérale de Lausanne (EPFL), ISIC-LSCI, BCH 3305, Lausanne, 1015, Switzerland.,Laboratory for Computational Molecular Design, Institute of Chemical Science and Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, 1015, Switzerland
| | - Hui-Jie Pan
- Laboratory of Inorganic Synthesis and Catalysis, Institute of Chemical Sciences and Engineering, École Polytechnique Fédérale de Lausanne (EPFL), ISIC-LSCI, BCH 3305, Lausanne, 1015, Switzerland
| | - Farzaneh Fadaei Tirani
- Laboratory of Inorganic Synthesis and Catalysis, Institute of Chemical Sciences and Engineering, École Polytechnique Fédérale de Lausanne (EPFL), ISIC-LSCI, BCH 3305, Lausanne, 1015, Switzerland
| | - Xile Hu
- Laboratory of Inorganic Synthesis and Catalysis, Institute of Chemical Sciences and Engineering, École Polytechnique Fédérale de Lausanne (EPFL), ISIC-LSCI, BCH 3305, Lausanne, 1015, Switzerland
| |
Collapse
|
13
|
Abstract
The advancements of quantum chemical methods and computer power allow detailed mechanistic investigations of metalloenzymes. In particular, both quantum chemical cluster and combined QM/MM approaches have been used, which have been proven to successfully complement experimental studies. This review starts with a brief introduction of nickel-dependent enzymes and then summarizes theoretical studies on the reaction mechanisms of these enzymes, including NiFe hydrogenase, methyl-coenzyme M reductase, nickel CO dehydrogenase, acetyl CoA synthase, acireductone dioxygenase, quercetin 2,4-dioxygenase, urease, lactate racemase, and superoxide dismutase.
Collapse
|
14
|
Hausinger RP, Desguin B, Fellner M, Rankin JA, Hu J. Nickel-pincer nucleotide cofactor. Curr Opin Chem Biol 2018; 47:18-23. [PMID: 30015232 DOI: 10.1016/j.cbpa.2018.06.019] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2018] [Revised: 06/15/2018] [Accepted: 06/19/2018] [Indexed: 10/28/2022]
Abstract
A novel organometallic cofactor, nickel pyridinium-3,5-dithiocarboxylic acid mononucleotide, was recently discovered in lactate racemase (LarA) of Lactobacillus plantarum. This review summarizes the substantial progress made in uncovering the function of this cofactor as a transient hydride acceptor in the LarA mechanism. The latest developments related to cofactor biosynthesis reveal insights into a pathway in which LarB serves as a nicotinic acid adenine dinucleotide hydrolase/carboxylase, LarE acts as a sacrificial sulfur transferase, and LarC functions as a nickel insertase, forming the nickel-pincer nucleotide cofactor that becomes covalently tethered to LarA in some bacteria. Bioinformatic studies reveal a widespread occurrence of larA, larB, larC, and larE orthologs in microorganisms, and additional roles for the cofactor are considered.
Collapse
Affiliation(s)
- Robert P Hausinger
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824, USA; Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA.
| | - Benoît Desguin
- Institute of Life Sciences, Université catholique de Louvain, B-1348 Louvain-La-Neuve, Belgium
| | - Matthias Fellner
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA
| | - Joel A Rankin
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA
| | - Jian Hu
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA; Department of Chemistry, Michigan State University, East Lansing, MI 48824, USA
| |
Collapse
|
15
|
Zhang T, Zhang X, Chung LW. Computational Insights into the Reaction Mechanisms of Nickel-Catalyzed Hydrofunctionalizations and Nickel-Dependent Enzymes. ASIAN J ORG CHEM 2018. [DOI: 10.1002/ajoc.201700645] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Tonghuan Zhang
- Department of Chemistry; South University of Science and Technology of China (SUSTech); Shenzhen 518055 China
- Lab of Computational Chemistry and Drug Design; Key Laboratory of Chemical Genomics; Peking University Shenzhen Graduate School; Shenzhen 518055 China
| | - Xiaoyong Zhang
- Department of Chemistry; South University of Science and Technology of China (SUSTech); Shenzhen 518055 China
| | - Lung Wa Chung
- Department of Chemistry; South University of Science and Technology of China (SUSTech); Shenzhen 518055 China
| |
Collapse
|
16
|
Rankin JA, Mauban RC, Fellner M, Desguin B, McCracken J, Hu J, Varganov SA, Hausinger RP. Lactate Racemase Nickel-Pincer Cofactor Operates by a Proton-Coupled Hydride Transfer Mechanism. Biochemistry 2018; 57:3244-3251. [PMID: 29489337 DOI: 10.1021/acs.biochem.8b00100] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Lactate racemase (LarA) of Lactobacillus plantarum contains a novel organometallic cofactor with nickel coordinated to a covalently tethered pincer ligand, pyridinium-3-thioamide-5-thiocarboxylic acid mononucleotide, but its function in the enzyme mechanism has not been elucidated. This study presents direct evidence that the nickel-pincer cofactor facilitates a proton-coupled hydride transfer (PCHT) mechanism during LarA-catalyzed lactate racemization. No signal was detected by electron paramagnetic resonance spectroscopy for LarA in the absence or presence of substrate, consistent with a +2 metal oxidation state and inconsistent with a previously proposed proton-coupled electron transfer mechanism. Pyruvate, the predicted intermediate for a PCHT mechanism, was observed in quenched solutions of LarA. A normal substrate kinetic isotope effect ( kH/ kD of 3.11 ± 0.17) was established using 2-α-2H-lactate, further supporting a PCHT mechanism. UV-visible spectroscopy revealed a lactate-induced perturbation of the cofactor spectrum, notably increasing the absorbance at 340 nm, and demonstrated an interaction of the cofactor with the inhibitor sulfite. A crystal structure of LarA provided greater resolution (2.4 Å) than previously reported and revealed sulfite binding to the pyridinium C4 atom of the reduced pincer cofactor, mimicking hydride reduction during a PCHT catalytic cycle. Finally, computational modeling supports hydride transfer to the cofactor at the C4 position or to the nickel atom, but with formation of a nickel-hydride species requiring dissociation of the His200 metal ligand. In aggregate, these studies provide compelling evidence that the nickel-pincer cofactor acts by a PCHT mechanism.
Collapse
Affiliation(s)
| | - Robert C Mauban
- Department of Chemistry , University of Nevada , Reno , Nevada 89557 , United States
| | | | - Benoît Desguin
- Institute of Life Sciences , Université catholique de Louvain , B-1348 Louvain-La-Neuve , Belgium
| | | | | | - Sergey A Varganov
- Department of Chemistry , University of Nevada , Reno , Nevada 89557 , United States
| | | |
Collapse
|
17
|
Wang WJ, Wei WJ, Liao RZ. Deciphering the chemoselectivity of nickel-dependent quercetin 2,4-dioxygenase. Phys Chem Chem Phys 2018; 20:15784-15794. [DOI: 10.1039/c8cp02683a] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
QM/MM calculations were performed to elucidate the reaction mechanism and chemoselectivity of 2,4-QueD. The protonation state of the first-shell ligand Glu74 plays an important role in dictating the selectivity.
Collapse
Affiliation(s)
- Wen-Juan Wang
- Key Laboratory of Material Chemistry for Energy Conversion and Storage
- Ministry of Education
- Hubei Key Laboratory of Bioinorganic Chemistry and Materia Medica
- Hubei Key Laboratory of Materials Chemistry and Service Failure
- School of Chemistry and Chemical Engineering
| | - Wen-Jie Wei
- Key Laboratory of Material Chemistry for Energy Conversion and Storage
- Ministry of Education
- Hubei Key Laboratory of Bioinorganic Chemistry and Materia Medica
- Hubei Key Laboratory of Materials Chemistry and Service Failure
- School of Chemistry and Chemical Engineering
| | - Rong-Zhen Liao
- Key Laboratory of Material Chemistry for Energy Conversion and Storage
- Ministry of Education
- Hubei Key Laboratory of Bioinorganic Chemistry and Materia Medica
- Hubei Key Laboratory of Materials Chemistry and Service Failure
- School of Chemistry and Chemical Engineering
| |
Collapse
|
18
|
|
19
|
Structural insights into the catalytic mechanism of a sacrificial sulfur insertase of the N-type ATP pyrophosphatase family, LarE. Proc Natl Acad Sci U S A 2017; 114:9074-9079. [PMID: 28784764 DOI: 10.1073/pnas.1704967114] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
The lar operon in Lactobacillus plantarum encodes five Lar proteins (LarA/B/C/D/E) that collaboratively synthesize and incorporate a niacin-derived Ni-containing cofactor into LarA, an Ni-dependent lactate racemase. Previous studies have established that two molecules of LarE catalyze successive thiolation reactions by donating the sulfur atom of their exclusive cysteine residues to the substrate. However, the catalytic mechanism of this very unusual sulfur-sacrificing reaction remains elusive. In this work, we present the crystal structures of LarE in ligand-free and several ligand-bound forms, demonstrating that LarE is a member of the N-type ATP pyrophosphatase (PPase) family with a conserved N-terminal ATP PPase domain and a unique C-terminal domain harboring the putative catalytic site. Structural analysis, combined with structure-guided mutagenesis, leads us to propose a catalytic mechanism that establishes LarE as a paradigm for sulfur transfer through sacrificing its catalytic cysteine residue.
Collapse
|
20
|
Desguin B, Soumillion P, Hausinger RP, Hols P. Unexpected complexity in the lactate racemization system of lactic acid bacteria. FEMS Microbiol Rev 2017; 41:S71-S83. [DOI: 10.1093/femsre/fux021] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Accepted: 04/11/2017] [Indexed: 12/30/2022] Open
|
21
|
Yu MJ, Chen SL. From NAD + to Nickel Pincer Complex: A Significant Cofactor Evolution Presented by Lactate Racemase. Chemistry 2017; 23:7545-7557. [PMID: 28374531 DOI: 10.1002/chem.201700405] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Indexed: 02/02/2023]
Abstract
Lactate racemase (LarA), a new nickel enzyme discovered recently, catalyzes the racemization between d- and l-lactates with a novel nickel pincer cofactor (Ni-PTTMN) derived from nicotinic acid. In this study, by using DFT and a 200-atom active-site model, LarA is revealed to employ a modified proton-coupled hydride-transfer mechanism in which a hydride is transferred to a cofactor pyridine carbon from the substrate α-carbon along with proton transfer from the substrate hydroxy group to a histidine, and then moved back from the opposite side. Tyr294 and Lys298 provide significant acceleration effects by orientating substrates and stabilizing the negative charge developing at the substrate hydroxy oxygen. The barrier was determined to be 12.0 kcal mol-1 , which reveals enhanced racemase activity relative to the LarA reaction using NAD+ -like cofactors. Compared with NAD+ , Ni-PTTMN has a stronger hydride-addition reactivity in moderate and high environmental polarity and may fit perfectly the moderately polar active site of LarA.
Collapse
Affiliation(s)
- Ming-Jia Yu
- Key Laboratory of Cluster Science of the Ministry of Education, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, 100081, P.R. China
| | - Shi-Lu Chen
- Key Laboratory of Cluster Science of the Ministry of Education, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, 100081, P.R. China
| |
Collapse
|
22
|
Wang B, Shaik S. The Nickel-Pincer Complex in Lactate Racemase Is an Electron Relay and Sink that acts through Proton-Coupled Electron Transfer. Angew Chem Int Ed Engl 2017; 56:10098-10102. [DOI: 10.1002/anie.201612065] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Indexed: 11/05/2022]
Affiliation(s)
- Binju Wang
- Institute of Chemistry and the Lise Meitner-Minerva Center for Computational Quantum Chemistry; The Hebrew University of Jerusalem; 91904 Jerusalem Israel
| | - Sason Shaik
- Institute of Chemistry and the Lise Meitner-Minerva Center for Computational Quantum Chemistry; The Hebrew University of Jerusalem; 91904 Jerusalem Israel
| |
Collapse
|
23
|
Wang B, Shaik S. The Nickel-Pincer Complex in Lactate Racemase Is an Electron Relay and Sink that acts through Proton-Coupled Electron Transfer. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201612065] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Binju Wang
- Institute of Chemistry and the Lise Meitner-Minerva Center for Computational Quantum Chemistry; The Hebrew University of Jerusalem; 91904 Jerusalem Israel
| | - Sason Shaik
- Institute of Chemistry and the Lise Meitner-Minerva Center for Computational Quantum Chemistry; The Hebrew University of Jerusalem; 91904 Jerusalem Israel
| |
Collapse
|