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Park HS, Byun BJ, Kang YK. Exploring Conformational Preferences of Leu-enkephalin Using the Conformational Search and Double-Hybrid DFT Energy Calculations. ACS OMEGA 2022; 7:27755-27768. [PMID: 35967045 PMCID: PMC9366962 DOI: 10.1021/acsomega.2c03942] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Accepted: 07/15/2022] [Indexed: 06/15/2023]
Abstract
The conformational preferences of Leu-enkephalin (Leu-Enk) were explored by the conformational search and density functional theory (DFT) calculations. By a combination of low-energy conformers of each residue, the initial structures of the neutral Leu-Enk were generated and optimized using the ECEPP3 force field in the gas phase. These structures were reoptimized at the HF/3-21G(d) and M06-2X levels of theory with 6-31G(d) and 6-31+G(d) basis functions. We finally located the 139 structures with the relative energy <10 kcal mol-1 in the gas phase, from which the structures of the corresponding zwitterionic Leu-Enk were generated and reoptimized at the M06-2X/6-31+G(d) level of theory using the implicit solvation model based on density (SMD) in water. The conformational preferences of Leu-Enk were analyzed using Gibbs free energies corrected by single-point energies calculated at the double-hybrid DSD-PBEP86-D3BJ/def2-TZVP level of theory in the gas phase and in water. The neutral Leu-Enk dominantly adopted a folded structure in the gas phase stabilized by three H-bonds with a βII'-bend-like motif at the Gly3-Phe4 sequence and a close contact between the side chains of Phe4 and Leu5. The zwitterionic Leu-Enk exhibited a folded structure in water stabilized by three H-bonds with double β-bends such as a βII' bend at the Gly2-Gly3 sequence and a βI bend at the Gly3-Phe4 sequence. The calculated ensemble-averaged distance between CGly2 α and CLeu5 α of the zwitterionic Leu-Enk in water is consistent with the value estimated from the simulated annealing using the distance constraints derived from nuclear Overhauser effect spectroscopy (NOESY) spectra in water. Interestingly, the preferred conformations of the neutral and zwitterionic Leu-Enk are new folded structures not predicted by earlier computational studies. According to the refined model of the zwitterionic Leu-Enk bound to δ-opioid receptor (δOR), there were favorable interactions of the terminal charged groups of Leu-Enk with the side chains of charged residues of δOR as well as a favorable CAryl···H interaction of the Phe4 residue of Leu-Enk with Trp284 of δOR. Hence, these favorable interactions would induce the folded structure of the zwitterionic Leu-Enk with double β-bends isolated in water into the "bioactive conformation" like an extended structure when binding to δOR.
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Affiliation(s)
- Hae Sook Park
- Department
of Nursing, Cheju Halla University, 38 Halladaehak-ro, Jeju, Jeju-do 63092, Republic of Korea
| | - Byung Jin Byun
- Drug
Discovery Center, JW Pharmaceutical Co.
Ltd., 2477 Nambusunhwan-ro, Seocho-gu, Seoul 06725, Republic
of Korea
| | - Young Kee Kang
- Department
of Chemistry, Chungbuk National University, 1 Chungdae-ro,
Seowon-gu, Cheongju, Chungbuk 28644, Republic of Korea
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2
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Selective MOR activity of DAPEA and Endomorphin-2 analogues containing a (R)-γ-Freidinger lactam in position two. Bioorg Chem 2021; 115:105219. [PMID: 34343741 DOI: 10.1016/j.bioorg.2021.105219] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 07/17/2021] [Accepted: 07/24/2021] [Indexed: 12/12/2022]
Abstract
The use of α-amino-γ lactam of Freidinger (Agl) may serve as an impressive method to increase the biological stability of peptides and an appropriate tool to elucidate their structure-activity relationships. The endomorphin-2 (EM-2) and [D-Ala2, des-Leu5] enkephalin amide (DAPEA) are two linear opioid tetrapeptides agonists of MOR and MOR/DOR respectively. Herein, we investigated the influence of the incorporation of (R/S)-Agl in position 2 and 3 on the biological profile of the aforementioned products in vitro and in vivo. Receptor radiolabeled displacement and functional assays were used to measure in vitro the binding affinity and receptors activation of the novel analogues. The mouse tail flick and formalin tests allowed to observe their antinociceptive effect in vivo. Data revealed that peptide A2D was able to selectively bind and activate MOR with a potent antinociceptive effect after intracerebroventricular (i.c.v.) administration, performing better than the parent compounds EM-2 and DAPEA. Molecular docking calculations helped us to understand the key role exerted by the Freidinger Agl moiety in A2D for the interaction with the MOR binding pocket.
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Bumbak F, Thomas T, Noonan-Williams BJ, Vaid TM, Yan F, Whitehead AR, Bruell S, Kocan M, Tan X, Johnson MA, Bathgate RAD, Chalmers DK, Gooley PR, Scott DJ. Conformational Changes in Tyrosine 11 of Neurotensin Are Required to Activate the Neurotensin Receptor 1. ACS Pharmacol Transl Sci 2020; 3:690-705. [PMID: 32832871 PMCID: PMC7432660 DOI: 10.1021/acsptsci.0c00026] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Indexed: 12/12/2022]
Abstract
Cell-cell communication via endogenous peptides and their receptors is vital for controlling all aspects of human physiology and most peptides signal through G protein-coupled receptors (GPCRs). Disordered peptides bind GPCRs through complex modes for which there are few representative crystal structures. The disordered peptide neurotensin (NT) is a neuromodulator of classical neurotransmitters such as dopamine and glutamate, through activation of neurotensin receptor 1 (NTS1). While several experimental structures show how NT binds NTS1, details about the structural dynamics of NT during and after binding NTS1, or the role of peptide dynamics on receptor activation, remain obscure. Here saturation transfer difference (STD) NMR revealed that the binding mode of NT fragment NT10-13 is heterogeneous. Epitope maps of NT10-13 at NTS1 suggested that tyrosine 11 (Y11) samples other conformations to those observed in crystal structures of NT-bound NTS1. Molecular dynamics (MD) simulations confirmed that when NT is bound to NTS1, residue Y11 can exist in two χ1 rotameric states, gauche plus (g+) or gauche minus (g-). Since only the g+ Y11 state is observed in all the structures solved to date, we asked if the g- state is important for receptor activation. NT analogues with Y11 replaced with 7-OH-Tic were synthesized to restrain the dynamics of the side chain. P(OH-TIC)IL bound NTS1 with the same affinity as NT10-13 but did not activate NTS1, instead acted as an antagonist. This study highlights that flexibility of Y11 in NT may be required for NT activation of NTS1.
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Affiliation(s)
- Fabian Bumbak
- The
Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria 3010, Australia
- Department
of Biochemistry and Molecular Biology, The
University of Melbourne, Parkville, Victoria 3010, Australia
- Bio21
Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Trayder Thomas
- Monash
Institute of Pharmaceutical Sciences, Monash
University, Parkville, Victoria 3052, Australia
| | - Billy J. Noonan-Williams
- Monash
Institute of Pharmaceutical Sciences, Monash
University, Parkville, Victoria 3052, Australia
| | - Tasneem M. Vaid
- The
Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria 3010, Australia
- Department
of Biochemistry and Molecular Biology, The
University of Melbourne, Parkville, Victoria 3010, Australia
- Bio21
Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Fei Yan
- Department
of Biochemistry and Molecular Biology, The
University of Melbourne, Parkville, Victoria 3010, Australia
- Bio21
Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Alice R. Whitehead
- The
Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Shoni Bruell
- The
Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Martina Kocan
- The
Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria 3010, Australia
- The School
of BioSciences, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Xuan Tan
- Department
of Chemistry, The University of Alabama
at Birmingham, Birmingham, Alabama 35294-1240, United States
| | - Margaret A. Johnson
- Department
of Chemistry, The University of Alabama
at Birmingham, Birmingham, Alabama 35294-1240, United States
| | - Ross A. D. Bathgate
- The
Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria 3010, Australia
- Department
of Biochemistry and Molecular Biology, The
University of Melbourne, Parkville, Victoria 3010, Australia
| | - David K. Chalmers
- Monash
Institute of Pharmaceutical Sciences, Monash
University, Parkville, Victoria 3052, Australia
| | - Paul R. Gooley
- Department
of Biochemistry and Molecular Biology, The
University of Melbourne, Parkville, Victoria 3010, Australia
- Bio21
Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Daniel J. Scott
- The
Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria 3010, Australia
- Department
of Biochemistry and Molecular Biology, The
University of Melbourne, Parkville, Victoria 3010, Australia
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Acevedo W, Temussi PA. The Origin of Unpleasant Aftertastes in Synthetic Sweeteners: A Hypothesis. Front Mol Biosci 2019; 5:119. [PMID: 30713843 PMCID: PMC6345712 DOI: 10.3389/fmolb.2018.00119] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Accepted: 12/28/2018] [Indexed: 11/24/2022] Open
Abstract
Most sweeteners are plagued with unwanted unpleasant aftertastes. Here we examined the possibility that one of the main reasons for this is the similarity of sweet and umami receptors. We performed docking calculations on models of sweet and umami receptors using as template the recently determined solid state structure of the first taste receptor, the medaka fish T1R2-T1R3 receptor. Our results show convincingly that sweeteners can be recognized also by the T1R1-T1R3 umami receptor, owing to the similarity of its architecture to that of the sweet receptor. We hypothesize that the T1R1-T1R3 receptor plays a key role in modulating the quality of sweet tastants, hinting at a simple explanation of their aftertaste. The prevailing ideas on taste coding favor strict labeling of taste cells, which would exclude that umami receptors can recognize other taste sensations. If some cross-talk based on the combinatorial model of taste is accepted, some sweet ligands can exert a bitter sensation. However, even if cross-talk is not admitted, direct stimulation of the umami receptor is bound to cause an aftertaste incompatible with good sweet quality.
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Affiliation(s)
- Waldo Acevedo
- Institute of Chemistry, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile
| | - Piero A Temussi
- Dipartimento di Chimica, Universita' di Napoli Federico II, Napoli, Italy.,Department of Basic and Clinical Neurosciences, King's College London, London, United Kingdom
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Zhou M, Luo RH, Hou XY, Wang RR, Yan GY, Chen H, Zhang RH, Shi JY, Zheng YT, Li R, Wei YQ. Synthesis, biological evaluation and molecular docking study of N -(2-methoxyphenyl)-6-((4-nitrophenyl)sulfonyl)benzamide derivatives as potent HIV-1 Vif antagonists. Eur J Med Chem 2017; 129:310-324. [DOI: 10.1016/j.ejmech.2017.01.010] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Revised: 01/06/2017] [Accepted: 01/08/2017] [Indexed: 01/28/2023]
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Abstract
This paper is the thirty-seventh consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2014 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior (endogenous opioids and receptors), and the roles of these opioid peptides and receptors in pain and analgesia (pain and analgesia); stress and social status (human studies); tolerance and dependence (opioid mediation of other analgesic responses); learning and memory (stress and social status); eating and drinking (stress-induced analgesia); alcohol and drugs of abuse (emotional responses in opioid-mediated behaviors); sexual activity and hormones, pregnancy, development and endocrinology (opioid involvement in stress response regulation); mental illness and mood (tolerance and dependence); seizures and neurologic disorders (learning and memory); electrical-related activity and neurophysiology (opiates and conditioned place preferences (CPP)); general activity and locomotion (eating and drinking); gastrointestinal, renal and hepatic functions (alcohol and drugs of abuse); cardiovascular responses (opiates and ethanol); respiration and thermoregulation (opiates and THC); and immunological responses (opiates and stimulants). This paper is the thirty-seventh consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2014 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior (endogenous opioids and receptors), and the roles of these opioid peptides and receptors in pain and analgesia (pain and analgesia); stress and social status (human studies); tolerance and dependence (opioid mediation of other analgesic responses); learning and memory (stress and social status); eating and drinking (stress-induced analgesia); alcohol and drugs of abuse (emotional responses in opioid-mediated behaviors); sexual activity and hormones, pregnancy, development and endocrinology (opioid involvement in stress response regulation); mental illness and mood (tolerance and dependence); seizures and neurologic disorders (learning and memory); electrical-related activity and neurophysiology (opiates and conditioned place preferences (CPP)); general activity and locomotion (eating and drinking); gastrointestinal, renal and hepatic functions (alcohol and drugs of abuse); cardiovascular responses (opiates and ethanol); respiration and thermoregulation (opiates and THC); and immunological responses (opiates and stimulants).
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Affiliation(s)
- Richard J Bodnar
- Department of Psychology and Neuropsychology Doctoral Sub-Program, Queens College, City University of New York, Flushing, NY 11367, United States.
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