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da Hora GCA, Nguyen JDM, Swanson JMJ. Can membrane composition traffic toxins? Mycolactone and preferential membrane interactions. Biophys J 2022; 121:4260-4270. [PMID: 36258678 PMCID: PMC9703097 DOI: 10.1016/j.bpj.2022.10.019] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 08/31/2022] [Accepted: 10/13/2022] [Indexed: 12/14/2022] Open
Abstract
Mycolactone is a cytotoxic and immunosuppressive macrolide produced by Mycobacterium ulcerans and the sole causative agent of the neglected tropical skin disease Buruli ulcer. The toxin acts by invading host cells and interacting with intracellular targets to disrupt multiple fundamental cellular processes. Mycolactone's amphiphilic nature enables strong interactions with lipophilic environments, including cellular membranes; however, the specificity of these interactions and the role of membranes in the toxin's pathogenicity remain unknown. It is likely that preferential interactions with lipophilic carriers play a key role in the toxin's distribution in the host, which, if understood, could provide insights to aid in the development of needed diagnostics for Buruli ulcer disease. In this work, molecular dynamics simulations were combined with enhanced free-energy sampling to characterize mycolactone's association with and permeation through models of the mammalian endoplasmic reticulum (ER) and plasma membranes (PMs). We find that increased order in the PMs not only leads to a different permeation mechanism compared with that in the ER membrane but also an energetic driving force for ER localization. Increased hydration, membrane deformation, and preferential interactions with unsaturated lipid tails stabilize the toxin in the ER membrane, while disruption of lipid packing is a destabilizing force in the PMs.
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Affiliation(s)
| | - John D M Nguyen
- Department of Chemistry, University of Utah, Salt Lake City, Utah
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Kang S, Noh C, Kang H, Shin JY, Kim SY, Kim S, Son MG, Park E, Song HK, Shin S, Lee S, Kim NK, Jung Y, Lee Y. Dynamics and Entropy of Cyclohexane Rings Control pH-Responsive Reactivity. JACS AU 2021; 1:2070-2079. [PMID: 34841418 PMCID: PMC8611792 DOI: 10.1021/jacsau.1c00354] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Indexed: 05/31/2023]
Abstract
Activation entropy (ΔS ‡) is not normally considered the main factor in determining the reactivity of unimolecular reactions. Here, we report that the intramolecular degradation of six-membered ring compounds is mainly determined by the ΔS ‡, which is strongly influenced by the ring-flipping motion and substituent geometry. Starting from the unique difference between the pH-dependent degradation kinetics of geometric isomers of 1,2-cyclohexanecarboxylic acid amide (1,2-CHCAA), where only the cis isomer can readily degrade under weakly acidic conditions (pH < 5.5), we found that the difference originated from the large difference in ΔS ‡ of 16.02 cal·mol-1·K-1. While cis-1,2-CHCAA maintains a preference for the classical chair cyclohexane conformation, trans-1,2-CHCAA shows dynamic interconversion between the chair and twisted boat conformations, which was supported by both MD simulations and VT-NMR analysis. Steric repulsion between the bulky 1,2-substituents of the trans isomer is one of the main reasons for the reduced energy barrier between ring conformations that facilitates dynamic ring inversion motions. Consequently, the more dynamic trans isomer exhibits much a larger loss in entropy during the activation process due to the prepositioning of the reactant than the cis isomer, and the pH-dependent degradation of the trans isomer is effectively suppressed. When the ring inversion motion is inhibited by an additional methyl substituent on the cyclohexane ring, the pH degradability can be dramatically enhanced for even the trans isomer. This study shows a unique example in which spatial arrangement and dynamic properties can strongly influence molecular reactivity in unimolecular reactions, and it will be helpful for the future design of a reactive structure depending on dynamic conformational changes.
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Affiliation(s)
- Sunyoung Kang
- Department
of Chemistry, Seoul National University, Seoul 08826, Republic of Korea
| | - Chanwoo Noh
- Department
of Chemistry, Seoul National University, Seoul 08826, Republic of Korea
| | - Hyosik Kang
- Department
of Chemistry, Gachon University, Seongnam, Gyunggido 13120, Republic of Korea
| | - Ji-Yeon Shin
- Advanced
Analysis Center, Korea Institute of Science
and Technology, Seoul 02792, Republic of Korea
- Department
of Life Sciences, Korea University, Seoul 02841, Republic of Korea
| | - So-Young Kim
- Advanced
Analysis Center, Korea Institute of Science
and Technology, Seoul 02792, Republic of Korea
| | - Seulah Kim
- Department
of Chemistry, Seoul National University, Seoul 08826, Republic of Korea
| | - Moon-Gi Son
- Department
of Chemistry, Seoul National University, Seoul 08826, Republic of Korea
| | - Eunseok Park
- Bruker
Biospin Korea, Seongnam, Gyunggido 13493, Republic of Korea
| | - Hyun Kyu Song
- Department
of Life Sciences, Korea University, Seoul 02841, Republic of Korea
| | - Seokmin Shin
- Department
of Chemistry, Seoul National University, Seoul 08826, Republic of Korea
| | - Sanghun Lee
- Department
of Chemistry, Gachon University, Seongnam, Gyunggido 13120, Republic of Korea
| | - Nak-Kyoon Kim
- Advanced
Analysis Center, Korea Institute of Science
and Technology, Seoul 02792, Republic of Korea
| | - YounJoon Jung
- Department
of Chemistry, Seoul National University, Seoul 08826, Republic of Korea
| | - Yan Lee
- Department
of Chemistry, Seoul National University, Seoul 08826, Republic of Korea
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Arifin, Yokogawa D, Schnupf U, Irle S. Statistical Mechanics-Based Theoretical Investigation of Solvation Effects on Glucose Anomer Preferences. J Phys Chem B 2018; 122:290-296. [PMID: 29271652 DOI: 10.1021/acs.jpcb.7b10270] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The importance of solvation effects on the stability of glucose anomers has been studied by the combination of quantum mechanics and statistical mechanics, namely, the reference interaction site model self-consistent field spatial electron density distribution. The preferences of α- and β-glucose in H2O are well reproduced with the obtained ratio of 35:65 for α- and β-glucose, respectively. Indirect interactions and bulk effects, described by the Onsager model, are relatively small compared to the direct solute-solvent interactions, especially in [DMIM]Cl and dimethyl sulfoxide. From the decomposition of solvation free energy and solvation structures, it can be seen that the interactions with the solvent molecules greatly contribute to the anomer preferences.
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Affiliation(s)
- Arifin
- Department of Chemistry, Graduate School of Science, Nagoya University , Chikusa, Nagoya 464-8601, Japan.,Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University , Chikusa, Nagoya 464-8602, Japan
| | - Daisuke Yokogawa
- Department of Chemistry, Graduate School of Science, Nagoya University , Chikusa, Nagoya 464-8601, Japan.,Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University , Chikusa, Nagoya 464-8602, Japan
| | - Udo Schnupf
- Mund-Lagowski Department of Chemistry & Biochemistry, Bradley University , Peoria 61625, Illinois, United States
| | - Stephan Irle
- Department of Chemistry, Graduate School of Science, Nagoya University , Chikusa, Nagoya 464-8601, Japan.,Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University , Chikusa, Nagoya 464-8602, Japan
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Matsumura Y, Sato H. An integral equation theory for solvation effects on the molecular structural fluctuation. J Chem Phys 2015; 143:014104. [DOI: 10.1063/1.4923038] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Yoshihiro Matsumura
- Department of Molecular Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan
| | - Hirofumi Sato
- Department of Molecular Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan
- Elements Strategy Initiative for Catalysts and Batteries (ESICB), Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan
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Takahashi H, Omi A, Morita A, Matubayasi N. Simple and exact approach to the electronic polarization effect on the solvation free energy: Formulation for quantum-mechanical/ molecular-mechanical system and its applications to aqueous solutions. J Chem Phys 2012; 136:214503. [DOI: 10.1063/1.4722347] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Matubayasi N, Takahashi H. Free-energy analysis of the electron-density fluctuation in the quantum-mechanical/molecular-mechanical simulation combined with the theory of energy representation. J Chem Phys 2012; 136:044505. [DOI: 10.1063/1.3677184] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
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