Differences in Interactions of Benzoic Acid and Benzoate with Interfaces

Peters, Benjamin; Groninger, Allison S.; Fontes, Fabio L.; Crick, Dean C.; Crans, Debbie C.

doi:10.1021/acs.langmuir.6b02073

Cited by 11 publications

(55 citation statements)

References 51 publications

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“…The NIC concentration was increased to obtain a greater signal to noise ratio in the 1 H NMR spectra of the RMs. Each aqueous stock solution was then pipetted into 2 mL aliquots and the pD (pD = pH + 0.4) 30–46 of each aliquot was adjusted using NaOD or DC1 solutions (5.0,1.0, and 0.1 M). The pD will be referred to as pH for the rest of this manuscript as is commonly done.…”

Section: Methodsmentioning

confidence: 99%

“…The pD will be referred to as pH for the rest of this manuscript as is commonly done. 30–46 The pD of the aliquots was adjusted to a range between 1.2 and 9.0 for later use in determination the pKa in D 2 O and in the w 0 16 RMs.…”

Section: Methodsmentioning

confidence: 99%

“…The pKa values were determined by plotting the chemical shifts of the samples at different pH values in D 2 O and in w 0 16 RMs and then taking the first derivative of the best fit curve using OriginPro Version 9.1 (see Figure S3). 30 …”

Section: Methodsmentioning

confidence: 99%

“…In these systems the placement and orientation could be identified by monitoring interactions with the AOT headgroup and/or lipid tails using ID and 2D NMR spectroscopic techniques. 3043–47 With the combination of these two model membrane systems (Figure 2), information about how the compounds in Figure 1 interact with membrane-like interfaces was obtained in this study.…”

Section: Introductionmentioning

confidence: 98%

“…34–36,37–38 To determine the molecular-detail interactions of small aromatic N-containing compound with an interface, aerosol-OT (AOT) reverse micelles (RM) 39–42 were examined. 30 · 43–47 RMs are self-assembled microemulsion that form at low water concentration. In these systems the placement and orientation could be identified by monitoring interactions with the AOT headgroup and/or lipid tails using ID and 2D NMR spectroscopic techniques.…”

Section: Introductionmentioning

confidence: 99%

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Structure Dependence of Pyridine and Benzene Derivatives on Interactions with Model Membranes

et al. 2018

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Pyridine based small molecule drugs, vitamins, and cofactors are vital for many cellular processes, but little is known about their interactions with membrane interfaces. These specific membrane interactions of these small molecules or ions can assist in diffusion across membranes or reach a membrane bound target This study explores how minor differences in small molecules (isoniazid, benzhydrazide, isonicotinamide, nicotinamide, picolinamide, and benzamide) can affect their interactions with model membranes. Langmuir monolayer studies of dipalmitoylphosphatidylcholine (DPPC) or dipalmitoylphosphatidylethanolamine (DPPE), in the presence of the molecules listed, show that isoniazid and isonicotinamide affect the DPPE monolayer at lower concentrations than the DPPC monolayer, demonstrating a preference for one phospholipid over the other. The Langmuir monolayer studies also suggest that nitrogen content and stereochemistry of the small molecule can affect the phospholipid monolayers differently. To determine the molecular interactions of the simple N-containing aromatic pyridines with a membrane-like interface, 1H 1D NMR and 1H-1H 2D NMR techniques were utilized to obtain information aboutposition and orientation of the molecules of interest within aerosol-OT (AOT) reverse micelles. These studies show that all six of the molecules reside near the AOT sulfonate headgroups and ester linkages in similar positions, but nicotinamide and picolinamide tilt at the water-AOT interface to varying degrees. Combined, these studies demonstrate that small structural changes of small N-containing molecules can affect their specific interactions with membrane-like interfaces, and specificity toward different membrane components.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

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Structure Dependence of Pyridine and Benzene Derivatives on Interactions with Model Membranes

et al. 2018

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Investigating Substrate Analogues for Mycobacterial MenJ: Truncated and Partially Saturated Menaquinones

et al. 2019

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Menaquinones (MKs) are essential for electron transport in prokaryotes, and importantly, partially saturated MKs represent a novel virulence factor. However, little is known regarding how the degree of saturation in the isoprenyl side chain influences conformation or quinone redox potential. MenJ is an enzyme that selectively reduces the second isoprene unit on MK-9 and is contextually essential for the survival of Mycobacterium tuberculosis in J774A.1 macrophage-like cells, suggesting that MenJ may be a conditional drug target for pathogenic mycobacteria. Therefore, fundamental information about the properties of this system is important, and we synthesized the simplest MKs, unsaturated MK-1 and the saturated analogue, MK-1(H2). Using two-dimensional nuclear magnetic resonance spectroscopy, we established that MK-1 and MK-1(H2) adopted similar folded–extended conformations (i.e., the isoprenyl side chain folds upward) in each solvent examined but the folded–extended conformations differed slightly between organic solvents. Saturation of the isoprenyl side chain slightly altered the MK-1 analogue conformation in each solvent. We used molecular mechanics to illustrate the MK-1 analogue conformations. The measured quinone redox potentials of MK-1 and MK-1(H2) differed between organic solvents (presumably due to differences in dielectric constants), and remarkably, an ∼20 mV semiquinone redox potential difference was observed between MK-1 and MK-1(H2) in pyridine, acetonitrile, and dimethyl sulfoxide, demonstrating that the degree of saturation in the isoprenyl side chain of MK-1 influences the quinone redox potential. Finally, MK-1 and MK-1(H2) interacted with Langmuir phospholipid monolayers and Aerosol-OT reverse micelle (RM) model membrane interfaces, where MK-1 adopted a slightly different folded conformation within the RM model membrane interface.

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A Synthetic Isoprenoid Lipoquinone, Menaquinone-2, Adopts a Folded Conformation in Solution and at a Model Membrane Interface

et al. 2017

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Menaquinones (naphthoquinones, MK) are isoprenoids that play key roles in the respiratory electron transport system of some prokaryotes by shuttling electrons between membrane-bound protein complexes acting as electron acceptors and donors. Menaquinone-2 (MK-2), a truncated MK, was synthesized, and the studies presented herein characterize the conformational and chemical properties of the hydrophobic MK-2 molecule. Using 2D NMR spectroscopy, we established for the first time that MK-2 has a folded conformation defined by the isoprenyl side-chain folding back over the napthoquinone in a U-shape, which depends on the specific environmental conditions found in different solvents. We used molecular mechanics to illustrate conformations found by the NMR experiments. The measured redox potentials of MK-2 differed in three organic solvents, where MK-2 was most easily reduced in DMSO, which may suggest a combination of solvent effect (presumably in part because of differences in dielectric constants) and/or conformational differences of MK-2 in different organic solvents. Furthermore, MK-2 was found to associate with the interface of model membranes represented by Langmuir phospholipid monolayers and Aerosol-OT (AOT) reverse micelles. MK-2 adopts a slightly different U-shaped conformation within reverse micelles compared to within solution, which is in sharp contrast to the extended conformations illustrated in literature for MKs.

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Differences in Interactions of Benzoic Acid and Benzoate with Interfaces

Cited by 11 publications

References 51 publications

Structure Dependence of Pyridine and Benzene Derivatives on Interactions with Model Membranes

Structure Dependence of Pyridine and Benzene Derivatives on Interactions with Model Membranes

Investigating Substrate Analogues for Mycobacterial MenJ: Truncated and Partially Saturated Menaquinones

A Synthetic Isoprenoid Lipoquinone, Menaquinone-2, Adopts a Folded Conformation in Solution and at a Model Membrane Interface

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