1
|
Asada Y, Tanaka S, Nagano H, Noguchi H, Yoshino A, Taga K, Yamamoto Y, Shervani Z. Morphology Observation of Two-Dimensional Monolayers of Model Proteins on Water Surface as Revealed by Dropping Method. Bioengineering (Basel) 2024; 11:366. [PMID: 38671787 PMCID: PMC11048086 DOI: 10.3390/bioengineering11040366] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Revised: 03/27/2024] [Accepted: 04/04/2024] [Indexed: 04/28/2024] Open
Abstract
We have investigated the morphology of two-dimensional monolayers of gramicidin-D (GD) and alamethicin (Al) formed on the water surface by the dropping method (DM) using surface tension measurement (STm), Brewster angle microscopy (BAM), and atomic force microscopy (AFM). Dynamic light scattering (DLS) revealed that GD in alcoholic solutions formed a dimeric helical structure. According to the CD and NMR spectroscopies, GD molecules existed in dimer form in methanol and lipid membrane environments. The STm results and BAM images revealed that the GD dimer monolayer was in a liquid expanded (LE) state, whereas the Al monolayer was in a liquid condensed (LC) state. The limiting molecular area (A0) was 6.2 ± 0.5 nm2 for the GD-dimer and 3.6 ± 0.5 nm2 for the Al molecule. The AFM images also showed that the molecular long axes of both the GD-dimer and Al were horizontal to the water surface. The stability of each monolayer was confirmed by the time dependence of the surface pressure (π) observed using the STm method. The DM monolayer preparation method for GD-dimer and Al peptide molecules is a useful technique for revealing how the model biological membrane's components assemble in two dimensions on the water surface.
Collapse
Affiliation(s)
- Yukie Asada
- Department of Life Science and Applied Chemistry, Graduate School of Engineering, Nagoya Institute of Technology, Nagoya 466-8555, Japan
| | - Shinya Tanaka
- Department of Life Science and Applied Chemistry, Graduate School of Engineering, Nagoya Institute of Technology, Nagoya 466-8555, Japan
| | - Hirotaka Nagano
- Department of Life Science and Applied Chemistry, Graduate School of Engineering, Nagoya Institute of Technology, Nagoya 466-8555, Japan
| | - Hiroki Noguchi
- Department of Life Science and Applied Chemistry, Graduate School of Engineering, Nagoya Institute of Technology, Nagoya 466-8555, Japan
| | - Akihiro Yoshino
- Department of Life Science and Applied Chemistry, Graduate School of Engineering, Nagoya Institute of Technology, Nagoya 466-8555, Japan
| | - Keijiro Taga
- Department of Life Science and Applied Chemistry, Graduate School of Engineering, Nagoya Institute of Technology, Nagoya 466-8555, Japan
| | - Yasushi Yamamoto
- Department of Life Science and Applied Chemistry, Graduate School of Engineering, Nagoya Institute of Technology, Nagoya 466-8555, Japan
| | - Zameer Shervani
- Food & Energy Security Research & Product Centre, Sendai 980-0871, Japan
| |
Collapse
|
2
|
Duan SF, Song L, Guo HY, Deng H, Huang X, Shen QK, Quan ZS, Yin XM. Research status of indole-modified natural products. RSC Med Chem 2023; 14:2535-2563. [PMID: 38107170 PMCID: PMC10718587 DOI: 10.1039/d3md00560g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Accepted: 10/16/2023] [Indexed: 12/19/2023] Open
Abstract
Indole is a heterocyclic compound formed by the fusion of a benzene ring and pyrrole ring, which has rich biological activity. Many indole-containing compounds have been sold on the market due to their excellent pharmacological activity. For example, vincristine and reserpine have been widely used in clinical practice. The diverse structures and biological activities of natural products provide abundant resources for the development of new drugs. Therefore, this review classifies natural products by structure, and summarizes the research progress of indole-containing natural product derivatives, their biological activities, structure-activity relationship and research mechanism which has been studied in the past 13 years, so as to provide a basis for the development of new drug development.
Collapse
Affiliation(s)
- Song-Fang Duan
- Key Laboratory of Natural Medicines of the Changbai Mountain, Ministry of Education, College of Pharmacy, Interdisciplinary Program of Biological Functional Molecules, College of Integration Science, Yanbian University Yanji 133002 China +86 0433 243 6020 +86 0433 243 6019
| | - Lei Song
- Yanbian University Hospital, Yanbian University Yanji 133002 People's Republic of China
| | - Hong-Yan Guo
- Key Laboratory of Natural Medicines of the Changbai Mountain, Ministry of Education, College of Pharmacy, Interdisciplinary Program of Biological Functional Molecules, College of Integration Science, Yanbian University Yanji 133002 China +86 0433 243 6020 +86 0433 243 6019
| | - Hao Deng
- Key Laboratory of Natural Medicines of the Changbai Mountain, Ministry of Education, College of Pharmacy, Interdisciplinary Program of Biological Functional Molecules, College of Integration Science, Yanbian University Yanji 133002 China +86 0433 243 6020 +86 0433 243 6019
| | - Xing Huang
- Key Laboratory of Natural Medicines of the Changbai Mountain, Ministry of Education, College of Pharmacy, Interdisciplinary Program of Biological Functional Molecules, College of Integration Science, Yanbian University Yanji 133002 China +86 0433 243 6020 +86 0433 243 6019
| | - Qing-Kun Shen
- Key Laboratory of Natural Medicines of the Changbai Mountain, Ministry of Education, College of Pharmacy, Interdisciplinary Program of Biological Functional Molecules, College of Integration Science, Yanbian University Yanji 133002 China +86 0433 243 6020 +86 0433 243 6019
| | - Zhe-Shan Quan
- Key Laboratory of Natural Medicines of the Changbai Mountain, Ministry of Education, College of Pharmacy, Interdisciplinary Program of Biological Functional Molecules, College of Integration Science, Yanbian University Yanji 133002 China +86 0433 243 6020 +86 0433 243 6019
| | - Xiu-Mei Yin
- Key Laboratory of Natural Medicines of the Changbai Mountain, Ministry of Education, College of Pharmacy, Interdisciplinary Program of Biological Functional Molecules, College of Integration Science, Yanbian University Yanji 133002 China +86 0433 243 6020 +86 0433 243 6019
| |
Collapse
|
3
|
Lander AJ, Mercado LD, Li X, Taily IM, Findlay BL, Jin Y, Luk LYP. Roles of inter- and intramolecular tryptophan interactions in membrane-active proteins revealed by racemic protein crystallography. Commun Chem 2023; 6:154. [PMID: 37464011 DOI: 10.1038/s42004-023-00953-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Accepted: 07/05/2023] [Indexed: 07/20/2023] Open
Abstract
Tryptophan is frequently found on the surface of membrane-associated proteins that interact with the lipid membrane. However, because of their multifaceted interactions, it is difficult to pinpoint the structure-activity relationship of each tryptophan residue. Here, we describe the use of racemic protein crystallography to probe dedicated tryptophan interactions of a model tryptophan-rich bacteriocin aureocin A53 (AucA) by inclusion and/or exclusion of potential ligands. In the presence of tetrahedral anions that are isosteric to the head group of phospholipids, distinct tryptophan H-bond networks were revealed. H-bond donation by W40 was critical for antibacterial activity, as its substitution by 1-methyltryptophan resulted in substantial loss of activity against bacterial clinical isolates. Meanwhile, exclusion of tetrahedral ions revealed that W3 partakes in formation of a dimeric interface, thus suggesting that AucA is dimeric in solution and dissociated to interact with the phosphate head group in the presence of the lipid membrane. Based on these findings, we could predict the tryptophan residue responsible for activity as well as the oligomeric state of a distant homologue lacticin Q (48%).
Collapse
Affiliation(s)
- Alexander J Lander
- School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff, CF10 3AT, UK
| | - Laura Domínguez Mercado
- Department of Chemistry & Biochemistry, Richard J. Renaud Science Complex, Concordia University, Montréal, Québec, H4B 1R6, Canada
| | - Xuefei Li
- School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff, CF10 3AT, UK
| | - Irshad Maajid Taily
- School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff, CF10 3AT, UK
| | - Brandon L Findlay
- Department of Chemistry & Biochemistry, Richard J. Renaud Science Complex, Concordia University, Montréal, Québec, H4B 1R6, Canada.
| | - Yi Jin
- Manchester Institute of Biotechnology, University of Manchester, Manchester, M1 7DN, UK.
| | - Louis Y P Luk
- School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff, CF10 3AT, UK.
| |
Collapse
|
4
|
Vinusri S, Gnanam R, Caroline R, Santhanakrishnan VP, Kandavelmani A. Anticancer Potential of Hydroxychavicol Derived from Piper betle L: An in Silico and Cytotoxicity Study. Nutr Cancer 2022; 74:3701-3713. [PMID: 35703834 DOI: 10.1080/01635581.2022.2085310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Piper betle L. is a popular medicinal plant in Asia, and extracts of the plant leaf are used for several therapeutics. It is known for its rich source of phenolic compounds, including hydroxychavicol. Hydroxychavicol is an allylbenzene that has gained much attention due to its anticancer properties. The current study quantified and purified hydroxychavicol from P. betle L. and predicted its anticancer competence through in silico and cytotoxicity studies. Leaf samples of 22 P. betle L. accessions from different locations of Tamil Nadu, India, were analyzed using reverse phase-high performance liquid chromatography for quantification of hydroxychavicol. The highest quantity of hydroxychavicol was obtained from the accession BV22 (89.2%). Chemical absorption, distribution, metabolism, excretion, and toxicity (ADMET) analysis of hydroxychavicol using SwissADME satisfied the physicochemical property guidelines of Lipinski's Rule of Five, ensuring its drug-likeness behavior. Molecular docking studies confirmed the interaction of hydroxychavicol with all 16 tested cancer targets. In Vitro MTT assay of hydroxychavicol in bone cancer cell lines (MG63) also demonstrated the anticancer competency, indicating the requirement to formulate the molecule as a drug in treating various types of cancers.
Collapse
Affiliation(s)
- S Vinusri
- Centre for Plant Molecular Biology and Biotechnology, Tamil Nadu Agricultural University, Coimbatore, India
| | - R Gnanam
- Centre for Plant Molecular Biology and Biotechnology, Tamil Nadu Agricultural University, Coimbatore, India
| | - R Caroline
- Centre for Plant Molecular Biology and Biotechnology, Tamil Nadu Agricultural University, Coimbatore, India
| | - V P Santhanakrishnan
- Centre for Plant Molecular Biology and Biotechnology, Tamil Nadu Agricultural University, Coimbatore, India
| | - A Kandavelmani
- Centre for Plant Molecular Biology and Biotechnology, Tamil Nadu Agricultural University, Coimbatore, India
| |
Collapse
|
5
|
Mohammad Hood MH, Tengku Abdul Hamid TH, Abdul Wahab RA, Huyop FZ, Kaya Y, Abdul Hamid AAA. Molecular interactions of trichoderma β-1,4-glucosidase (ThBglT12) with mycelial cell wall components of phytopathogenic Macrophomina phaseolina. J Biomol Struct Dyn 2022; 41:2831-2847. [PMID: 35174777 DOI: 10.1080/07391102.2022.2039772] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Efficacy of a β-1,4-glucosidase from Trichoderma harzianum T12 (ThBglT12) in disrupting the cell wall of the phytopathogenic fungus M. phaseolina (Macrophomina phaseolina) was studied, as the underlying molecular mechanisms of cell wall recognition remains elusive. In this study, the binding location identified by a consensus of residues predicted by COACH tool, blind docking, and multiple sequence alignment revealed that molecular recognition by ThBglT12 occurred through interactions between the α-1,3-glucan, β-1,3-glucan, β-1,3/1,4-glucan, and chitin components of M. phaseolina, with corresponding binding energies of -7.4, -7.6, -7.5 and -7.8 kcal/mol. The residue consensus verified the participation of Glu172, Tyr304, Trp345, Glu373, Glu430, and Trp431 in the active site pocket of ThBglT12 to bind the ligands, of which Trp345 was the common interacting residue. Root mean square deviation (RMSD), root mean square fluctuation (RMSF), total energy, and minimum distance calculation from molecular dynamics (MD) simulation further confirmed the stability and the closeness of the binding ligands into the ThBglT12 active site pocket. The h-bond occupancy by Glu373 and Trp431 instated the role of the nucleophile for substrate recognition and specificity, crucial for cleaving the β-1,4 linkage. Further investigation showed that the proximity of Glu373 to the anomeric carbon of β-1,3/1,4-glucan (3.5 Å) and chitin (5.5 Å) indicates the nucleophiles' readiness to form enzyme-substrate intermediates. Plus, the neighboring water molecule appeared to be correctly positioned and oriented towards the anomeric carbon to hydrolyze the β-1,3/1,4-glucan and chitin, in less than 4.0 Å. In a nutshell, the study verified that the ThBglT12 is a good alternative fungicide to inhibit the growth of M. phaseolina.Communicated by Ramaswamy H. Sarma.
Collapse
Affiliation(s)
- Mohammad Hakim Mohammad Hood
- Department of Biotechnology, Kulliyyah of Science, International Islamic University Malaysia (IIUM), Kuantan, Pahang, Malaysia
| | - Tengku Haziyamin Tengku Abdul Hamid
- Department of Biotechnology, Kulliyyah of Science, International Islamic University Malaysia (IIUM), Kuantan, Pahang, Malaysia.,Research Unit for Bioinformatics and Computational Biology (RUBIC), Kulliyyah of Science, International Islamic University Malaysia (IIUM), Kuantan, Pahang, Malaysia
| | - Roswanira Abdul Abdul Wahab
- Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia, Johor, Malaysia.,Enzyme Technology and Green Synthesis Group, Faculty of Science, Universiti Teknologi Malaysia, UTM Johor Bahru, Malaysia
| | - Fahrul Zaman Huyop
- Department of Biosciences, Faculty of Science, Universiti Teknologi Malaysia, Johor, Malaysia
| | - Yilmaz Kaya
- Department of Agricultural Biotechnology, Faculty of Agriculture, Ondokuz Mayis University, Turkey
| | - Azzmer Azzar Abdul Abdul Hamid
- Department of Biotechnology, Kulliyyah of Science, International Islamic University Malaysia (IIUM), Kuantan, Pahang, Malaysia.,Research Unit for Bioinformatics and Computational Biology (RUBIC), Kulliyyah of Science, International Islamic University Malaysia (IIUM), Kuantan, Pahang, Malaysia
| |
Collapse
|
6
|
Pal S, Koeppe RE, Chattopadhyay A. Membrane electrostatics sensed by tryptophan anchors in hydrophobic model peptides depends on non-aromatic interfacial amino acids: implications in hydrophobic mismatch. Faraday Discuss 2021; 232:330-346. [PMID: 34549729 DOI: 10.1039/d0fd00065e] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
WALPs are synthetic α-helical membrane-spanning peptides that constitute a well-studied system for exploring hydrophobic mismatch. These peptides represent a simplified consensus motif for transmembrane domains of intrinsic membrane proteins due to their hydrophobic core of alternating leucine and alanine flanked by membrane-anchoring aromatic tryptophan residues. Although the modulation of mismatch responses in WALPs by tryptophan anchors has been reported earlier, there have been limited attempts to utilize the intrinsic tryptophan fluorescence of this class of peptides in mismatch sensors. We have previously shown, utilizing the red edge excitation shift (REES) approach, that interfacial WALP tryptophan residues in fluid phase bilayers experience a dynamically constrained membrane microenvironment. Interestingly, emerging reports suggest the involvement of non-aromatic interfacially localized residues in modulating local structure and dynamics in WALP analogs. In this backdrop, we have explored the effect of interfacial amino acids, such as lysine (in KWALPs) and glycine (in GWALPs), on the tryptophan microenvironment of WALP analogs in zwitterionic and negatively charged membranes. We show that interfacial tryptophans in KWALP and GWALP experience a more restricted microenvironment, as reflected in the substantial increase in magnitude of REES and apparent rotational correlation time, relative to those in WALP in zwitterionic membranes. Interestingly, in contrast to WALP, the tryptophan anchors in KWALP and GWALP appear insensitive to the presence of negatively charged lipids in the membrane. These results reveal a subtle interplay between non-aromatic flanking residues in transmembrane helices and negatively charged lipids at the membrane interface, which could modulate the membrane microenvironment experienced by interfacially localized tryptophan residues. Since interfacial tryptophans are known to influence mismatch responses in WALPs, our results highlight the possibility of utilizing the fluorescence signatures of tryptophans in membrane proteins or model peptides such as WALP as markers for assessing protein responses to hydrophobic mismatch. More importantly, these results constitute one of the first reports on the influence of lipid headgroup charge in fine-tuning hydrophobic mismatch in membrane bilayers, thereby enriching the existing framework of hydrophobic mismatch.
Collapse
Affiliation(s)
- Sreetama Pal
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad 500 007, India. .,CSIR-Indian Institute of Chemical Technology, Hyderabad 500 007, India.,Academy of Scientific and Innovative Research, Ghaziabad 201 002, India
| | - Roger E Koeppe
- Department of Chemistry and Biochemistry, University of Arkansas, AR 72701, USA
| | - Amitabha Chattopadhyay
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad 500 007, India. .,Academy of Scientific and Innovative Research, Ghaziabad 201 002, India
| |
Collapse
|
7
|
Li X, İlk S, Linares-Pastén JA, Liu Y, Raina DB, Demircan D, Zhang B. Synthesis, Enzymatic Degradation, and Polymer-Miscibility Evaluation of Nonionic Antimicrobial Hyperbranched Polyesters with Indole or Isatin Functionalities. Biomacromolecules 2021; 22:2256-2271. [PMID: 33900740 PMCID: PMC8382248 DOI: 10.1021/acs.biomac.1c00343] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
![]()
Most macromolecular
antimicrobials are ionic and thus lack miscibility/compatibility
with nonionic substrate materials. In this context, nonionic hyperbranched
polyesters (HBPs) with indole or isatin functionality were rationally
designed, synthesized, and characterized. Antimicrobial disk diffusion
assay indicated that these HBPs showed significant antibacterial activity
against 8 human pathogenic bacteria compared to small molecules with
indole or isatin groups. According to DSC measurements, up to 20%
indole-based HBP is miscible with biodegradable polyesters (polyhydroxybutyrate
or polycaprolactone), which can be attributed to the favorable hydrogen
bonding between the N–H moiety of indole and the C=O
of polyesters. HBPs with isatin or methylindole were completely immiscible
with the same matrices. None of the HBPs leaked out from plastic matrix
after being immersed in water for 5 days. The incorporation of indole
into HBPs as well as small molecules facilitated their enzymatic degradation
with PETase from Ideonella sakaiensis, while isatin
had a complex impact. Molecular docking simulations of monomeric molecules
with PETase revealed different orientations of the molecules at the
active site due to the presence of indole or isatin groups, which
could be related to the observed different enzymatic degradation behavior.
Finally, biocompatibility analysis with a mammalian cell line showed
the negligible cytotoxic effect of the fabricated HBPs.
Collapse
Affiliation(s)
- Xiaoya Li
- Centre for Analysis and Synthesis, Department of Chemistry, Lund University, P.O. Box 124, SE-22100 Lund, Sweden
| | - Sedef İlk
- Faculty of Medicine, Department of Immunology, Niğde Ömer Halisdemir University, 51240 Niǧde, Turkey.,School of Engineering Sciences in Chemistry, Biotechnology and Health, Department of Chemistry, Division of Glycoscience, KTH Royal Institute of Technology, SE-10691 Stockholm, Sweden
| | - Javier A Linares-Pastén
- Division of Biotechnology, Department of Chemistry, Lund University, P.O. Box 124, 22100 Lund, Sweden
| | - Yang Liu
- Faculty of Medicine, Department of Clinical Sciences, Orthopedics, Lund University, 22100 Lund, Sweden
| | - Deepak Bushan Raina
- Faculty of Medicine, Department of Clinical Sciences, Orthopedics, Lund University, 22100 Lund, Sweden
| | - Deniz Demircan
- Centre for Analysis and Synthesis, Department of Chemistry, Lund University, P.O. Box 124, SE-22100 Lund, Sweden
| | - Baozhong Zhang
- Centre for Analysis and Synthesis, Department of Chemistry, Lund University, P.O. Box 124, SE-22100 Lund, Sweden
| |
Collapse
|
8
|
|
9
|
The Uniqueness of Tryptophan in Biology: Properties, Metabolism, Interactions and Localization in Proteins. Int J Mol Sci 2020; 21:ijms21228776. [PMID: 33233627 PMCID: PMC7699789 DOI: 10.3390/ijms21228776] [Citation(s) in RCA: 65] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 11/16/2020] [Accepted: 11/17/2020] [Indexed: 12/14/2022] Open
Abstract
Tryptophan (Trp) holds a unique place in biology for a multitude of reasons. It is the largest of all twenty amino acids in the translational toolbox. Its side chain is indole, which is aromatic with a binuclear ring structure, whereas those of Phe, Tyr, and His are single-ring aromatics. In part due to these elaborate structural features, the biosynthetic pathway of Trp is the most complex and the most energy-consuming among all amino acids. Essential in the animal diet, Trp is also the least abundant amino acid in the cell, and one of the rarest in the proteome. In most eukaryotes, Trp is the only amino acid besides Met, which is coded for by a single codon, namely UGG. Due to the large and hydrophobic π-electron surface area, its aromatic side chain interacts with multiple other side chains in the protein, befitting its strategic locations in the protein structure. Finally, several Trp derivatives, namely tryptophylquinone, oxitriptan, serotonin, melatonin, and tryptophol, have specialized functions. Overall, Trp is a scarce and precious amino acid in the cell, such that nature uses it parsimoniously, for multiple but selective functions. Here, the various aspects of the uniqueness of Trp are presented in molecular terms.
Collapse
|
10
|
Bera S, Xue B, Rehak P, Jacoby G, Ji W, Shimon LJW, Beck R, Král P, Cao Y, Gazit E. Self-Assembly of Aromatic Amino Acid Enantiomers into Supramolecular Materials of High Rigidity. ACS NANO 2020; 14:1694-1706. [PMID: 31944667 PMCID: PMC7123433 DOI: 10.1021/acsnano.9b07307] [Citation(s) in RCA: 76] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Accepted: 01/16/2020] [Indexed: 05/12/2023]
Abstract
Most natural biomolecules may exist in either of two enantiomeric forms. Although in nature, amino acid biopolymers are characterized by l-type homochirality, incorporation of d-amino acids in the design of self-assembling peptide motifs has been shown to significantly alter enzyme stability, conformation, self-assembly behavior, cytotoxicity, and even therapeutic activity. However, while functional metabolite assemblies are ubiquitous throughout nature and play numerous important roles including physiological, structural, or catalytic functions, the effect of chirality on the self-assembly nature and function of single amino acids is not yet explored. Herein, we investigated the self-assembly mechanism of amyloid-like structure formation by two aromatic amino acids, phenylalanine (Phe) and tryptophan (Trp), both previously found as extremely important for the nucleation and self-assembly of aggregation-prone peptide regions into functional structures. Employing d-enantiomers, we demonstrate the critical role that amino acid chirality plays in their self-assembly process. The kinetics and morphology of pure enantiomers is completely altered upon their coassembly, allowing to fabricate different nanostructures that are mechanically more robust. Using diverse experimental techniques, we reveal the different molecular arrangement and self-assembly mechanism of the dl-racemic mixtures that resulted in the formation of advanced supramolecular materials. This study provides a simple yet sophisticated engineering model for the fabrication of attractive materials with bionanotechnological applications.
Collapse
Affiliation(s)
- Santu Bera
- School
of Molecular Cell Biology and Biotechnology, George S. Wise Faculty
of Life Sciences, Tel Aviv University, Ramat Aviv 69978, Israel
| | - Bin Xue
- Collaborative
Innovation Center of Advanced Microstructures, National Laboratory
of Solid State Microstructure, Department of Physics, Nanjing University, Nanjing, Jiangsu 210093, People’s Republic of China
| | - Pavel Rehak
- Department
of Chemistry, University of Illinois at
Chicago, Chicago, Illinois 60607, United States
| | - Guy Jacoby
- The
Raymond and Beverly Sackler School of Physics and Astronomy, Tel Aviv University, Tel Aviv 69978, Israel
| | - Wei Ji
- School
of Molecular Cell Biology and Biotechnology, George S. Wise Faculty
of Life Sciences, Tel Aviv University, Ramat Aviv 69978, Israel
| | - Linda J. W. Shimon
- Department
of Chemical Research Support, Weizmann Institute
of Science, Rehovot 76100, Israel
| | - Roy Beck
- The
Raymond and Beverly Sackler School of Physics and Astronomy, Tel Aviv University, Tel Aviv 69978, Israel
| | - Petr Král
- Department
of Chemistry, University of Illinois at
Chicago, Chicago, Illinois 60607, United States
- Department
of Biopharmaceutical Sciences, University
of Illinois at Chicago, Chicago, Illinois 60607, United States
| | - Yi Cao
- Collaborative
Innovation Center of Advanced Microstructures, National Laboratory
of Solid State Microstructure, Department of Physics, Nanjing University, Nanjing, Jiangsu 210093, People’s Republic of China
| | - Ehud Gazit
- School
of Molecular Cell Biology and Biotechnology, George S. Wise Faculty
of Life Sciences, Tel Aviv University, Ramat Aviv 69978, Israel
| |
Collapse
|
11
|
Reiter R, Zaitseva E, Baaken G, Halimeh I, Behrends JC, Zumbuehl A. Activity of the Gramicidin A Ion Channel in a Lipid Membrane with Switchable Physical Properties. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:14959-14966. [PMID: 31645105 DOI: 10.1021/acs.langmuir.9b02752] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Lipid bilayer membranes formed from the artificial 1,3-diamidophospholipid Pad-PC-Pad have the remarkable property that their hydrophobic thickness can be modified in situ: the particular arrangement of the fatty acid chains in Pad-PC-Pad allows them to fully interdigitate below 37 °C, substantially thinning the membrane with respect to the noninterdigitated state. Two stimuli, traversing the main phase transition temperature of the lipid or addition of cholesterol, have previously been shown to disable the interdigitated state. Both manipulations cause an increase in hydrophobic thickness of about 25 Å due to enhanced conformational entropy of the lipids. Here, we characterize the interdigitated state using electrophysiological recordings from free-standing lipid-membranes formed on micro structured electrode cavity arrays. Compared to standard membranes made from 1,2-diphytanoyl-sn-glycero-3-phosphocholin (DPhPC), pure Pad-PC-Pad membranes at room temperature had lowered electroporation threshold and higher capacitance. Ion channel formation by the peptide Gramicidin A was clearly facilitated in pure Pad-PC-Pad membranes at room temperature, with activity occurring at significantly lower peptide concentrations and channel dwell times increased by 2 orders of magnitude with respect to DPhPC-membranes. Both elevation of temperature beyond the phase transition and addition of cholesterol reduced channel dwell times, as expected if the reduced membrane thickness stabilized channel formation due to decreased hydrophobic mismatch.
Collapse
Affiliation(s)
- Renate Reiter
- Institute of Physics , University of Freiburg , Hermann-Herder-Strasse 3 , 79104 , Freiburg , Germany
- Freiburg Centre for Interactive Materials and Bioinspired Technologies (FIT) , 79110 , Freiburg , Germany
| | - Ekaterina Zaitseva
- Laboratory for Membrane Physiology and Technology, Department of Physiology, Faculty of Medicine , University of Freiburg , Hermann-Herder-Strasse 7 , 79104 , Freiburg , Germany
- Ionera Technologies GmbH , Hermann-Herder-Strasse 7 , 79104 , Freiburg , Germany
| | - Gerhard Baaken
- Ionera Technologies GmbH , Hermann-Herder-Strasse 7 , 79104 , Freiburg , Germany
| | - Ibrahim Halimeh
- Laboratory for Membrane Physiology and Technology, Department of Physiology, Faculty of Medicine , University of Freiburg , Hermann-Herder-Strasse 7 , 79104 , Freiburg , Germany
- Ionera Technologies GmbH , Hermann-Herder-Strasse 7 , 79104 , Freiburg , Germany
| | - Jan C Behrends
- Freiburg Centre for Interactive Materials and Bioinspired Technologies (FIT) , 79110 , Freiburg , Germany
- Laboratory for Membrane Physiology and Technology, Department of Physiology, Faculty of Medicine , University of Freiburg , Hermann-Herder-Strasse 7 , 79104 , Freiburg , Germany
- Freiburg Centre for Materials Research , (FMF) Stefan Meier Strasse 21 , 79104 , Freiburg , Germany
| | - Andreas Zumbuehl
- National Center of Competence in Research in Chemical Biology , Geneva CH-1211 , Switzerland
| |
Collapse
|
12
|
Rajasekharan SK, Lee JH, Ravichandran V, Kim JC, Park JG, Lee J. Nematicidal and insecticidal activities of halogenated indoles. Sci Rep 2019; 9:2010. [PMID: 30765810 PMCID: PMC6375993 DOI: 10.1038/s41598-019-38561-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Accepted: 01/02/2019] [Indexed: 12/25/2022] Open
Abstract
Parasite death via ion channel activations is the hallmark of anthelmintic and antiparasitic drugs. Glutamate gated chloride channel (GluCl) is a prominent targets for drug selection and design in parasitology. We report several iodine-fluorine based lead activators of GluCl by computational studies and structure-activity relationship analysis. 5-Fluoro-4-iodo-1H-pyrrolo [2, 3-b] pyridine and 5-iodoindole were bioactive hits that displayed in vitro anthelmintic and insecticidal activities against Bursaphelenchus xylophilus, Meloidogyne incognita, and Tenebrio molitor. Two important findings stood out: (i) 5F4IPP induced parasite death, and interacted proficiently with Gln219 amino acid of pentameric GluCl in docking analysis, and (ii) 5-iodoindole appeared to act by forming giant vacuoles in nematodes, which led to a form of non-apoptotic death known as methuosis. The study suggests halogenated-indoles and 1H-pyrrolo [2, 3-b] pyridine derivatives be regarded potential biocides for plant-parasitic nematodes and insects, and warrants further research on the mode of actions, and field investigations.
Collapse
Affiliation(s)
| | - Jin-Hyung Lee
- School of Chemical Engineering, Yeungnam University, Gyeongsan, 38541, Republic of Korea
| | - Vinothkannan Ravichandran
- Shandong University-Helmholtz Institute of Biotechnology, School of Life Science, Shandong University, Jinan, P. R. China
| | - Jin-Cheol Kim
- Department of Agricultural Chemistry, Institute of Environmentally Friendly Agriculture, College of Agriculture and Life Sciences, Chonnam National University, Gwangju, Republic of Korea
| | - Jae Gyu Park
- Advanced Bio Convergence Center, Pohang Technopark Foundation, Pohang, 37668, Republic of Korea
| | - Jintae Lee
- School of Chemical Engineering, Yeungnam University, Gyeongsan, 38541, Republic of Korea.
| |
Collapse
|
13
|
Pal S, Koeppe RE, Chattopadhyay A. Wavelength-Selective Fluorescence of a Model Transmembrane Peptide: Constrained Dynamics of Interfacial Tryptophan Anchors. J Fluoresc 2018; 28:1317-1323. [PMID: 30225736 DOI: 10.1007/s10895-018-2293-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Accepted: 09/03/2018] [Indexed: 11/27/2022]
Abstract
WALPs are prototypical, α-helical transmembrane peptides that represent a consensus sequence for transmembrane segments of integral membrane proteins and serve as excellent models for exploring peptide-lipid interactions and hydrophobic mismatch in membranes. Importantly, the WALP peptides are in direct contact with the lipids. They consist of a central stretch of alternating hydrophobic alanine and leucine residues capped at both ends by tryptophans. In this work, we employ wavelength-selective fluorescence approaches to explore the intrinsic fluorescence of tryptophan residues in WALP23 in 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) membranes. Our results show that the four tryptophan residues in WALP23 exhibit an average red edge excitation shift (REES) of 6 nm, implying their localization at the membrane interface, characterized by a restricted microenvironment. This result is supported by fluorescence anisotropy and lifetime measurements as a function of wavelength displayed by WALP23 tryptophans in POPC membranes. These results provide a new approach based on intrinsic fluorescence of interfacial tryptophans to address protein-lipid interaction and hydrophobic mismatch.
Collapse
Affiliation(s)
- Sreetama Pal
- CSIR-Indian Institute of Chemical Technology, Uppal Road, Hyderabad, 500 007, India
- Academy of Scientific and Innovative Research, Ghaziabad, India
| | - Roger E Koeppe
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, AR, 72701, USA
| | - Amitabha Chattopadhyay
- Academy of Scientific and Innovative Research, Ghaziabad, India.
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad, 500 007, India.
| |
Collapse
|
14
|
Reddy DN, Singh S, Ho CMW, Patel J, Schlesinger P, Rodgers S, Doctor A, Marshall GR. Design, synthesis, and biological evaluation of stable β 6.3-Helices: Discovery of non-hemolytic antibacterial peptides. Eur J Med Chem 2018; 149:193-210. [PMID: 29501941 DOI: 10.1016/j.ejmech.2018.02.057] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Revised: 01/26/2018] [Accepted: 02/16/2018] [Indexed: 11/25/2022]
Abstract
Gramicidin A, a topical antibiotic made from alternating L and D amino acids, is characterized by its wide central pore; upon insertion into membranes, it forms channels that disrupts ion gradients. We present helical peptidomimetics with this characteristic wide central pore that have been designed to mimic gramicidin A channels. Mimetics were designed using molecular modeling focused on oligomers of heterochiral dipeptides of proline analogs, in particular azaproline (AzPro). Molecular Dynamics simulations in water confirmed the stability of the designed helices. A sixteen-residue Formyl-(AzPro-Pro)8-NHCH2CH2OH helix was synthesized as well as a full thirty-two residue Cbz-(AzPro-Pro)16-OtBu channels. No liposomal lysis activity was observed suggesting lack of channel formation, possibly due to inappropriate hydrogen-bonding interactions in the membrane. These peptidomimetics also did not hemolyze red blood cells, unlike gramicidin A.
Collapse
Affiliation(s)
- Damodara N Reddy
- Department of Biochemistry & Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA.
| | - Sukrit Singh
- Department of Biochemistry & Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Chris M W Ho
- Department of Biochemistry & Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Janki Patel
- Department of Biochemistry & Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Paul Schlesinger
- Department of Cell Biology & Physiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Stephen Rodgers
- Department of Pediatrics, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Allan Doctor
- Department of Pediatrics, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Garland R Marshall
- Department of Biochemistry & Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA.
| |
Collapse
|
15
|
Falcone N, Basak S, Dong B, Syed J, Ferranco A, Lough A, She Z, Kraatz HB. A Ferrocene-Tryptophan Conjugate: The Role of the Indolic Nitrogen in Supramolecular Assembly. Chempluschem 2017; 82:1282-1289. [DOI: 10.1002/cplu.201700407] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Indexed: 12/11/2022]
Affiliation(s)
- Natashya Falcone
- Department of Chemical Engineering and Applied Chemistry; University of Toronto; 200 College St Toronto ON M5S 3E5 Canada
- Department of Physical and Environmental Sciences; University of Toronto Scarborough; 1065 Military Trail Toronto ON M1C 1A4 Canada
| | - Shibaji Basak
- Department of Physical and Environmental Sciences; University of Toronto Scarborough; 1065 Military Trail Toronto ON M1C 1A4 Canada
| | - Bin Dong
- Department of Chemistry and Chemical Engineering, School of Chemistry and Biological Engineering; University of Science and Technology Beijing; Beijing 100083 P. R. China
| | - Jebriel Syed
- Department of Physical and Environmental Sciences; University of Toronto Scarborough; 1065 Military Trail Toronto ON M1C 1A4 Canada
| | - Annaleizle Ferranco
- Department of Physical and Environmental Sciences; University of Toronto Scarborough; 1065 Military Trail Toronto ON M1C 1A4 Canada
- Department of Chemistry; University of Toronto; 80 St. George Street Toronto ON M5S 3H6 Canada
| | - Alan Lough
- Department of Chemistry; University of Toronto; 80 St. George Street Toronto ON M5S 3H6 Canada
| | - Zhe She
- Department of Physical and Environmental Sciences; University of Toronto Scarborough; 1065 Military Trail Toronto ON M1C 1A4 Canada
| | - Heinz-Bernhard Kraatz
- Department of Chemical Engineering and Applied Chemistry; University of Toronto; 200 College St Toronto ON M5S 3E5 Canada
- Department of Physical and Environmental Sciences; University of Toronto Scarborough; 1065 Military Trail Toronto ON M1C 1A4 Canada
- Department of Chemistry; University of Toronto; 80 St. George Street Toronto ON M5S 3H6 Canada
| |
Collapse
|
16
|
Zhang W, Markiewicz BN, Doerksen RS, Smith AB, Gai F. C≡N stretching vibration of 5-cyanotryptophan as an infrared probe of protein local environment: what determines its frequency? Phys Chem Chem Phys 2016; 18:7027-34. [PMID: 26343769 PMCID: PMC4775302 DOI: 10.1039/c5cp04413h] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Recently it has been suggested that the C≡N stretching vibration of a tryptophan analog, 5-cyanotryptophan, could be used as an infrared probe of the local environment, especially the hydration status, of tryptophan residues in proteins. However, the factors that influence the frequency of this vibrational mode are not understood. To determine these factors, herein we carried out linear and nonlinear infrared measurements on the C≡N stretching vibration of the sidechain of 5-cyanotryptophan, 3-methyl-5-cyanoindole, in a series of protic and aprotic solvents. We found that while the C≡N stretching frequencies obtained in these solvents do not correlate well with any individual Kamlet-Taft solvent parameter, i.e., π* (polarizability), β (hydrogen bond accepting ability), and α (hydrogen bond donating ability), they do however, collapse on a straight line when plotted against σ = π* + β - α. This linear relationship provides a firm indication that both specific interactions, i.e., hydrogen-bonding interactions with the C≡N (through α) and indole N-H (through β) groups, and non-specific interactions with the molecule (through π*) work together to determine the C≡N stretching frequency, thus laying a quantitative framework for applying 5-cyanotryptophan to investigate the microscopic environment of proteins in a site-specific manner. Furthermore, two-dimensional and pump-probe infrared measurements revealed that a significant portion (∼31%) of the ground state bleach signal has a decay time constant of ∼12.3 ps, due to an additional vibrational relaxation channel, making it possible to use 5-cyanotryptophan to probe dynamics occurring on a timescale on the order of tens of picoseconds.
Collapse
Affiliation(s)
- Wenkai Zhang
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104, USA. and The Ultrafast Optical Processes Laboratory, University of Pennsylvania, Philadelphia, PA 19104, USA
| | | | - Rosalie S Doerksen
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104, USA.
| | - Amos B Smith
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104, USA.
| | - Feng Gai
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104, USA. and The Ultrafast Optical Processes Laboratory, University of Pennsylvania, Philadelphia, PA 19104, USA
| |
Collapse
|
17
|
Thigulla Y, Akula M, Trivedi P, Ghosh B, Jha M, Bhattacharya A. Synthesis and anti-cancer activity of 1,4-disubstituted imidazo[4,5-c]quinolines. Org Biomol Chem 2016; 14:876-83. [DOI: 10.1039/c5ob01650a] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Synthesis of 4-substituted imidazo[4,5-c]quinolines using a Yb(OTf)3 catalyzed modified Pictet–Spengler reaction as the key final step.
Collapse
Affiliation(s)
- Yadagiri Thigulla
- Department of Chemistry
- Birla Institute of Technology and Science-Pilani (Hyderabad Campus)
- Hyderabad-500078
- India
| | - Mahesh Akula
- Department of Chemistry
- Birla Institute of Technology and Science-Pilani (Hyderabad Campus)
- Hyderabad-500078
- India
| | - Prakruti Trivedi
- Department of Pharmacy
- Birla Institute of Technology and Science-Pilani (Hyderabad Campus)
- Hyderabad-500078
- India
| | - Balaram Ghosh
- Department of Pharmacy
- Birla Institute of Technology and Science-Pilani (Hyderabad Campus)
- Hyderabad-500078
- India
| | - Mukund Jha
- Department of Biology and Chemistry
- Nipissing University
- North Bay
- Canada
| | - Anupam Bhattacharya
- Department of Chemistry
- Birla Institute of Technology and Science-Pilani (Hyderabad Campus)
- Hyderabad-500078
- India
| |
Collapse
|
18
|
Chaturvedi D, Mahalakshmi R. Juxtamembrane tryptophans have distinct roles in defining the OmpX barrel-micelle boundary and facilitating protein-micelle association. FEBS Lett 2015; 588:4464-71. [PMID: 25448987 DOI: 10.1016/j.febslet.2014.10.017] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Revised: 10/15/2014] [Accepted: 10/16/2014] [Indexed: 10/24/2022]
Abstract
Defining the span of the transmembrane region, a key requirement to ensure correct folding, stability and function of bacterial outer membrane β-barrels, is assisted by the amphipathic property of tryptophan. We demonstrate the unique and distinctive properties of the interface Trp76 and Trp140 of outer membrane protein X, and map their positional relevance to the refolding process, barrel formation and the resulting stability in dodecylphosphocholine micelles. The solvent-exposed Trp76 displays a rigid interfacial localization, whereas Trp140 is relatively micelle-solvated and contributes to barrel folding and global OmpX stability. Kinetic contribution to OmpX stability is influenced by the two tryptophans. Differential associations of the indoles with the detergent milieu therefore contribute to micelle-assisted β-barrel folding and concomitant OmpX stability.
Collapse
Affiliation(s)
- Deepti Chaturvedi
- Molecular Biophysics Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal 462023, India
| | | |
Collapse
|
19
|
Fuentealba D, López JJ, Palominos M, Salas CO, Soto-Arriaza MA. Gramicidin conformational changes during riboflavin photosensitized oxidation in solution and the effect of N-methylation of tryptophan residues. Photochem Photobiol Sci 2015; 14:748-56. [DOI: 10.1039/c4pp00414k] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
During riboflavin mediated photo-oxidation, gramicidin changes from intertwined to monomeric conformation (disaggregation), while the methylated derivative is not photo-oxidized.
Collapse
Affiliation(s)
- Denis Fuentealba
- Laboratorio de Química Biológica
- Departamento de Química Física
- Facultad de Química
- Pontificia Universidad Católica de Chile
- Santiago
| | - Jhon J. López
- Departamento de Química Orgánica
- Facultad de Química
- Pontificia Universidad Católica de Chile
- Santiago
- Chile
| | - Marco Palominos
- Laboratorio de Química Biológica
- Departamento de Química Física
- Facultad de Química
- Pontificia Universidad Católica de Chile
- Santiago
| | - Cristian O. Salas
- Departamento de Química Orgánica
- Facultad de Química
- Pontificia Universidad Católica de Chile
- Santiago
- Chile
| | - Marco A. Soto-Arriaza
- Laboratorio de Química Biológica
- Departamento de Química Física
- Facultad de Química
- Pontificia Universidad Católica de Chile
- Santiago
| |
Collapse
|
20
|
Ahmed I, Jhung SH. Effective adsorptive removal of indole from model fuel using a metal-organic framework functionalized with amino groups. JOURNAL OF HAZARDOUS MATERIALS 2014; 283:544-550. [PMID: 25464294 DOI: 10.1016/j.jhazmat.2014.10.002] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Revised: 10/01/2014] [Accepted: 10/04/2014] [Indexed: 06/04/2023]
Abstract
Nitrogen-containing compounds (NCCs) should be removed from fuels because of the negative effect of NCCs on the environment and catalyst stability. NCCs are composed of basic materials such as quinoline (QUI) and neutral materials such as indole (IND). The NCCs can be removed by various methods including adsorption. Compared with basic NCCs, neutral NCCs are more difficult to remove through adsorption due to their less affinity toward adsorbents. In this report, adsorption of IND (as one of the representative neutral NCCs) was studied over the metal-organic frameworks (MOFs), UiO-66 and UiO-66-NH2, which contain terephthalate and aminoterephthalate linkers, respectively. In spite of the reduced porosity of UiO-66-NH2, the adsorption capacity of IND was improved upto 46% when compared with pristine UiO-66. Therefore, the additional amino group in the MOF imparts extra adsorption capability on the MOF. For a detailed investigation, adsorption of other NCCs such as QUI, pyrrole, and methylpyrrole was studied. The improved adsorption of IND over amino-functionalized MOFs could be attributed to the improved interaction of IND with the MOF via H-bonding because of the NH2 group. In addition to this remarkable improvement in IND adsorption, UiO-66-NH2 could be regenerated several times for the adsorption of IND by simple solvent washing.
Collapse
Affiliation(s)
- Imteaz Ahmed
- Department of Chemistry and Green-Nano Materials Research Center, Kyungpook National University, Daegu 702-701, Republic of Korea
| | - Sung Hwa Jhung
- Department of Chemistry and Green-Nano Materials Research Center, Kyungpook National University, Daegu 702-701, Republic of Korea.
| |
Collapse
|