1
|
Santoro M, Coi A, Lipucci Di Paola M, Bianucci AM, Gainotti S, Mollo E, Taruscio D, Vittozzi L, Bianchi F. Rare disease registries classification and characterization: a data mining approach. Public Health Genomics 2015; 18:113-22. [PMID: 25677717 DOI: 10.1159/000369993] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Accepted: 11/19/2014] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND The European Commission and Patients Organizations identify rare disease registries (RDRs) as strategic instruments to develop research and improve knowledge in the field of rare diseases. Interoperability between RDRs is needed for research activities, validation of therapeutic treatments, and public health actions. Sharing and comparing information requires a uniform and standardized way of data collection, so levels of interconnection between RDRs with similar aims and/or nature of data should be identified. The objective of this study is to define a classification and characterization of RDRs in order to identify different profiles and informative needs. METHODS Exploratory statistical analyses (cluster analysis and random forest) were applied to data derived from the EPIRARE project ('Building Consensus and Synergies for the EU Rare Disease Patient Registration') survey on the activities and needs of RDRs. RESULTS The cluster analysis identified 3 main typologies of RDRs: public health, clinical and genetic research, and treatment registries. The analysis of the most informative variables, identified by the random forest method, led to the characterization of 3 types of RDRs and the definition of different profiles and informative needs. CONCLUSIONS These results represent a useful source of information to facilitate the harmonization and interconnection of RDRs in accordance with the different profiles identified. It could help sharing the information between RDRs with similar profiles and, whenever possible, interconnections between registries with different profiles.
Collapse
Affiliation(s)
- Michele Santoro
- Institute of Clinical Physiology, National Council of Research, University of Pisa, Pisa, Italy
| | | | | | | | | | | | | | | | | |
Collapse
|
2
|
Podestà A, Rossi S, Massarelli I, Carpi S, Adinolfi B, Fogli S, Bianucci AM, Nieri P. Selection of a human butyrylcholinesterase-like antibody single-chain variable fragment resistant to AChE inhibitors from a phage library expressed in E. coli. MAbs 2014; 6:1084-93. [PMID: 24675419 DOI: 10.4161/mabs.28635] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Organophosphates are potent poisoning agents that cause severe cholinergic toxicity. Current treatment has been reported to be unsatisfactory and novel antidotes are needed. In this study, we used a single-chain variable fragment (scFv) library to select a recombinant antibody fragment (WZ1-14.2.1) with butyrylcholinesterase-like catalytic activity by using an innovative method integrating genetic selection and the bait-and-switch strategy. Ellman assay demonstrated that WZ1-14.2.1 has Michaelis-Menten kinetics in the hydrolysis of all the three substrates used, acetylthiocholine, propionylthiocholine and butyrylthiocholine. Notably, the catalytic activity was resistant to the following acetylcholinesterase inhibitors: neostigmine, iso-OMPA, chlorpyrifos oxon, dichlorvos, and paraoxon ethyl. Otherwise, the enzymatic activity of WZ1-14.2.1 was inhibited by the selective butyrylcholinesterase inhibitor, ethopropazine, and by the Ser-blocking agent phenylmethanesuphonyl fluoride. A hypothetical 3D structure of the WZ1-14.2.1 catalytic site, compatible with functional results, is proposed on the basis of a molecular modeling analysis.
Collapse
|
3
|
Coi A, Bianucci AM. Combining structure- and ligand-based approaches for studies of interactions between different conformations of the hERG K+ channel pore and known ligands. J Mol Graph Model 2013; 46:93-104. [PMID: 24185260 DOI: 10.1016/j.jmgm.2013.10.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2013] [Revised: 10/01/2013] [Accepted: 10/03/2013] [Indexed: 11/13/2022]
Abstract
Drug-induced insurgence of cardiotoxic effects signaled by the prolongation of the QT interval in the electrocardiogram, has the potential to evolve into a characteristic arrhythmic event named Torsade de Pointes (TdP). Although several different mechanisms can theoretically lead to prolonged QT interval, most of drugs showing this side effect, prolong the cardiac repolarization time through the inhibition of the rapid component of the delayed repolarizing current (IKr) which in humans is carried by a K(+) channel protein encoded by hERG. In this study, four 3D-models, representing different conformational states of hERG K(+) channel, were built by a homology-based technique. A dataset of 59 compounds was collected from the literature and rationally selected according to the availability of IC50 values derived from whole-cell patch clamp performed at 37 °C on HEK cells. Molecular docking was carried out on each one of the four conformations of the channel, hundreds of docking-based molecular descriptors were obtained and used, together with other 2D and 3D molecular descriptors, to develop QSAR models. The statistical parameters describing the accordance between predicted and experimental data and the interpretation of the QSAR models enabled us to assess the reliability of the four 3D-models of the channel pore, thus allowing to look in more depth at binding modes and key features of the interactions occurring between the hERG K(+) channel and ligands endowed of blocking activity.
Collapse
Affiliation(s)
- Alessio Coi
- INSTM (Consorzio National Interuniversity Consortium of Materials Science and Technology), Via Giusti 9, 50121 Firenze, Italy
| | | |
Collapse
|
4
|
Isolani ME, Abril JF, Saló E, Deri P, Bianucci AM, Batistoni R. Planarians as a model to assess in vivo the role of matrix metalloproteinase genes during homeostasis and regeneration. PLoS One 2013; 8:e55649. [PMID: 23405188 PMCID: PMC3566077 DOI: 10.1371/journal.pone.0055649] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2012] [Accepted: 12/28/2012] [Indexed: 12/12/2022] Open
Abstract
Matrix metalloproteinases (MMPs) are major executors of extracellular matrix remodeling and, consequently, play key roles in the response of cells to their microenvironment. The experimentally accessible stem cell population and the robust regenerative capabilities of planarians offer an ideal model to study how modulation of the proteolytic system in the extracellular environment affects cell behavior in vivo. Genome-wide identification of Schmidtea mediterranea MMPs reveals that planarians possess four mmp-like genes. Two of them (mmp1 and mmp2) are strongly expressed in a subset of secretory cells and encode putative matrilysins. The other genes (mt-mmpA and mt-mmpB) are widely expressed in postmitotic cells and appear structurally related to membrane-type MMPs. These genes are conserved in the planarian Dugesia japonica. Here we explore the role of the planarian mmp genes by RNA interference (RNAi) during tissue homeostasis and regeneration. Our analyses identify essential functions for two of them. Following inhibition of mmp1 planarians display dramatic disruption of tissues architecture and significant decrease in cell death. These results suggest that mmp1 controls tissue turnover, modulating survival of postmitotic cells. Unexpectedly, the ability to regenerate is unaffected by mmp1(RNAi). Silencing of mt-mmpA alters tissue integrity and delays blastema growth, without affecting proliferation of stem cells. Our data support the possibility that the activity of this protease modulates cell migration and regulates anoikis, with a consequent pivotal role in tissue homeostasis and regeneration. Our data provide evidence of the involvement of specific MMPs in tissue homeostasis and regeneration and demonstrate that the behavior of planarian stem cells is critically dependent on the microenvironment surrounding these cells. Studying MMPs function in the planarian model provides evidence on how individual proteases work in vivo in adult tissues. These results have high potential to generate significant information for development of regenerative and anti cancer therapies.
Collapse
Affiliation(s)
- Maria Emilia Isolani
- Dipartimento di Biologia, Università di Pisa, Pisa, Italy
- Dipartimento di Scienze Farmaceutiche, Università di Pisa, Pisa, Italy
| | - Josep F. Abril
- Departament de Genètica, Universitat de Barcelona and Institut de Biomedicina de la Universitat de Barcelona, Barcelona, Catalonia, Spain
| | - Emili Saló
- Departament de Genètica, Universitat de Barcelona and Institut de Biomedicina de la Universitat de Barcelona, Barcelona, Catalonia, Spain
| | - Paolo Deri
- Dipartimento di Biologia, Università di Pisa, Pisa, Italy
| | | | | |
Collapse
|
5
|
Isolani ME, Pietra D, Balestrini L, Borghini A, Deri P, Imbriani M, Bianucci AM, Batistoni R. The in vivo effect of chelidonine on the stem cell system of planarians. Eur J Pharmacol 2012; 686:1-7. [DOI: 10.1016/j.ejphar.2012.03.036] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2011] [Revised: 03/20/2012] [Accepted: 03/23/2012] [Indexed: 11/16/2022]
|
6
|
Bianucci AM, Massarelli I, Chiellini F, Eidelman C, Chiellini E. Design of highly specific ligands of fibrin for therapeutic applications. Journal of Biomaterials Science, Polymer Edition 2012; 15:1203-22. [PMID: 15503635 DOI: 10.1163/1568562041753052] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The work presented here is aimed at designing high-affinity ligands for the fibrin gamma (312-324) epitope. This epitope is specific for fibrin recognition, as it is exposed only on the fibrin surface, while in fibrinogen it is buried in the protein bulk. This property makes it very useful for therapeutic applications. In fact, it may be exploited in driving systems for targeted delivery of thrombolytic drugs toward the specific compartment where they are needed. It will then allow avoidance of serious unwanted side effects produced by a conventional systemic administration. The approach chosen for designing putative ligands is based on the known three-dimensional (3D) structure of the epitope. A wide virtual library made up of oligo-peptides and analogues designed by a combinatorial approach, on the basis of chemical complementarity criteria, has been screened by means of a docking/scoring approach (DOCK program). The peculiarity of the problem under study required a considerable effort in finding a method enabling the experimental validation of the design work results. In fact the selected biological target is absolutely new, so that neither a endogenous, nor a synthetic high-affinity ligand is known up to now. It does not allow for the validation of computational results by means of classical binding tests based on the use of known labeled high-affinity ligands. Preliminary binding essayes were so carried out by means of the Plasmon Surface Resonance (PSR) technique. The experimental results suggested that most of the molecules predicted to be good ligands by means of the selected computational tools, could carry the wanted affinity toward the selected target.
Collapse
Affiliation(s)
- Anna Maria Bianucci
- Department of Pharmaceutical Science, University of Pisa, via Bonanno Pisano 6, 56126 Pisa, Italy
| | | | | | | | | |
Collapse
|
7
|
Chiellini G, Rapposelli S, Zhu J, Massarelli I, Saraceno M, Bianucci AM, Plum LA, Clagett-Dame M, DeLuca HF. Synthesis and biological activities of vitamin D-like inhibitors of CYP24 hydroxylase. Steroids 2012; 77:212-23. [PMID: 22133546 PMCID: PMC3539163 DOI: 10.1016/j.steroids.2011.11.007] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2011] [Revised: 11/14/2011] [Accepted: 11/15/2011] [Indexed: 01/08/2023]
Abstract
Selective inhibitors of CYP24A1 represent an important synthetic target in a search for novel vitamin D compounds of therapeutic value. In the present work, we show the synthesis and biological properties of two novel side chain modified 2-methylene-19-nor-1,25(OH)(2)D(3) analogs, the 22-imidazole-1-yl derivative 2 (VIMI) and the 25-N-cyclopropylamine compound 3 (CPA1), which were efficiently prepared in convergent syntheses utilizing the Lythgoe type Horner-Wittig olefination reaction. When tested in a cell-free assay, both compounds were found to be potent competitive inhibitors of CYP24A1, with the cyclopropylamine analog 3 exhibiting an 80-1 selective inhibition of CYP24A1 over CYP27B1. Addition of 3 to a mouse osteoblast culture sustained the level of 1,25(OH)(2)D(3), further demonstrating its effectiveness in CYP24A1 inhibition. Importantly, the in vitro effects on human promyeloid leukemia (HL-60) cell differentiation by 3 were nearly identical to those of 1,25(OH)(2)D(3) and in vivo the compound showed low calcemic activity. Finally, the results of preliminary theoretical studies provide useful insights to rationalize the ability of analog 3 to selectively inhibit the cytochrome P450 isoform CYP24A1.
Collapse
Affiliation(s)
- Grazia Chiellini
- Department of Biochemistry, University of Wisconsin-Madison, 433 Babcock Drive, Madison, WI 53706-1544, USA
- Dipartimento di Scienze dell’Uomo e dell’Ambiente, Università di Pisa, via Roma 55, 56126 Pisa, Italy
| | - Simona Rapposelli
- Dipartimento di Scienze Farmaceutiche, Università di Pisa, via Bonanno 6, 56126 Pisa, Italy
| | - Jinge Zhu
- Department of Biochemistry, University of Wisconsin-Madison, 433 Babcock Drive, Madison, WI 53706-1544, USA
| | - Ilaria Massarelli
- Istituto Nazionale per la Scienza e la Tecnologia dei Materiali, via Giusti 9, 50121 Firenze, Italy
| | - Marilena Saraceno
- Dipartimento di Scienze Farmaceutiche, Università di Pisa, via Bonanno 6, 56126 Pisa, Italy
| | - Anna Maria Bianucci
- Dipartimento di Scienze Farmaceutiche, Università di Pisa, via Bonanno 6, 56126 Pisa, Italy
- International Centre for Studies and Research in Biomedicine (ICB), Luxembourg
| | - Lori A. Plum
- Department of Biochemistry, University of Wisconsin-Madison, 433 Babcock Drive, Madison, WI 53706-1544, USA
| | - Margaret Clagett-Dame
- Department of Biochemistry, University of Wisconsin-Madison, 433 Babcock Drive, Madison, WI 53706-1544, USA
| | - Hector F. DeLuca
- Department of Biochemistry, University of Wisconsin-Madison, 433 Babcock Drive, Madison, WI 53706-1544, USA
- Corresponding author. Tel.: +1 608 262 1620; fax: +1 608 262 7122. (H.F. DeLuca)
| |
Collapse
|
8
|
Pietra D, Imbriani M, Borghini A, Giorgi I, Settimo FD, Breschi MC, Campa M, Batoni G, Brancatisano FL, Bianucci AM. Structure-Activity Relationships on Purine and 2,3-Dihydropurine Derivatives as Antitubercular Agents: a Data Mining Approach. Chem Biol Drug Des 2011; 78:718-24. [DOI: 10.1111/j.1747-0285.2011.01181.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
|
9
|
Massarelli I, Imbriani M, Chiellini F, Chiellini E, Bianucci AM. Identification of selective ligands for human fibrin recognition using high-throughput docking. J Mol Recognit 2011; 24:824-32. [DOI: 10.1002/jmr.1122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
10
|
Pietra D, Borghini A, Breschi MC, Bianucci AM. Enhancer and competitive allosteric modulation model for G-protein-coupled receptors. J Theor Biol 2010; 267:663-75. [DOI: 10.1016/j.jtbi.2010.08.024] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2010] [Revised: 08/04/2010] [Accepted: 08/20/2010] [Indexed: 10/19/2022]
|
11
|
Borghini A, Crotti P, Pietra D, Favero L, Bianucci AM. Chemical reactivity predictions: Use of data mining techniques for analyzing regioselective azidolysis of epoxides. J Comput Chem 2010; 31:2612-9. [DOI: 10.1002/jcc.21556] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
12
|
Coi A, Massarelli I, Saraceno M, Carli N, Testai L, Calderone V, Bianucci AM. Quantitative Structure-Activity Relationship Models for Predicting Biological Properties, Developed by Combining Structure- and Ligand-Based Approaches: An Application to the Human Ether-a-go-go-Related Gene Potassium Channel Inhibition. Chem Biol Drug Des 2009; 74:416-33. [DOI: 10.1111/j.1747-0285.2009.00873.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
|
13
|
Coi A, Fiamingo FL, Livi O, Calderone V, Martelli A, Massarelli I, Bianucci AM. QSAR studies on BK channel activators. Bioorg Med Chem 2009; 17:319-25. [DOI: 10.1016/j.bmc.2008.10.068] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2008] [Revised: 10/10/2008] [Accepted: 10/30/2008] [Indexed: 10/21/2022]
|
14
|
Coi A, Massarelli I, Testai L, Calderone V, Bianucci AM. Identification of “toxicophoric” features for predicting drug-induced QT interval prolongation. Eur J Med Chem 2008; 43:2479-88. [DOI: 10.1016/j.ejmech.2007.12.025] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2007] [Revised: 12/07/2007] [Accepted: 12/11/2007] [Indexed: 11/26/2022]
|
15
|
Giorgi I, Biagi G, Bianucci AM, Borghini A, Livi O, Leonardi M, Pietra D, Calderone V, Martelli A. N6-1,3-Diphenylurea derivatives of 2-phenyl-9-benzyladenines and 8-azaadenines: Synthesis and biological evaluation as allosteric modulators of A2A adenosine receptors. Eur J Med Chem 2008; 43:1639-47. [DOI: 10.1016/j.ejmech.2007.10.021] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2006] [Revised: 10/15/2007] [Accepted: 10/16/2007] [Indexed: 10/22/2022]
|
16
|
Saraceno M, Coi A, Bianucci AM. Molecular modelling of human CYP2D6 and molecular docking of a series of ajmalicine- and quinidine-like inhibitors. Int J Biol Macromol 2008; 42:362-71. [DOI: 10.1016/j.ijbiomac.2008.01.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2007] [Revised: 12/18/2007] [Accepted: 01/22/2008] [Indexed: 10/22/2022]
|
17
|
Chicca A, Pellati F, Adinolfi B, Matthias A, Massarelli I, Benvenuti S, Martinotti E, Bianucci AM, Bone K, Lehmann R, Nieri P. Cytotoxic activity of polyacetylenes and polyenes isolated from roots of Echinacea pallida. Br J Pharmacol 2008; 153:879-85. [PMID: 18193076 DOI: 10.1038/sj.bjp.0707639] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND AND PURPOSE The n-hexane extracts of the roots of three medicinally used Echinacea species exhibited cytotoxic activity on human cancer cell lines, with Echinacea pallida found to be the most cytotoxic. Acetylenes are present in E. pallida lipophilic extracts but essentially absent in extracts from the other two species. In the present study, the cytotoxic effects of five compounds, two polyacetylenes (namely, 8-hydroxy-pentadeca-(9E)-ene-11,13-diyn-2-one (1) and pentadeca-(9E)-ene-11,13-diyne-2,8-dione (3)) and three polyenes (namely, 8-hydroxy-pentadeca-(9E,13Z)-dien-11-yn-2-one (2), pentadeca-(9E,13Z)-dien-11-yne-2,8-dione (4) and pentadeca-(8Z,13Z)-dien-11-yn-2-one (5)), isolated from the n-hexane extract of E. pallida roots by bioassay-guided fractionation, were investigated and the potential bioavailability of these compounds in the extract was studied. EXPERIMENTAL APPROACH Cytotoxic effects were assessed on human pancreatic MIA PaCa-2 and colonic COLO320 cancer cell lines. Cell viability was evaluated by the WST-1 assay and apoptotic cell death by the cytosolic internucleosomal DNA enrichment and the caspase 3/7 activity tests. Caco-2 cell monolayers were used to assess the potential bioavailability of the acetylenes. KEY RESULTS The five compounds exhibited concentration-dependent cytotoxicity in both cell types, with a greater potency in the colonic cancer cells. Apoptotic cell death was found to be involved in the cytotoxic effect of the most active, compound 5. Compounds 2 and 5 were found to cross the Caco-2 monolayer with apparent permeabilities above 10 x 10(-6) cm s(-1). CONCLUSIONS AND IMPLICATIONS Compounds isolated from n-hexane extracts of E. pallida roots have a direct cytotoxicity on cancer cells and good potential for absorption in humans when taken orally.
Collapse
Affiliation(s)
- A Chicca
- Department of Psychiatry, Neurobiology, Pharmacology and Biotechnology, University of Pisa, Pisa, Italy
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
18
|
Coi A, Bianucci AM, Bonomi F, Rasmussen P, Mura GM, Ganadu ML. Structural perturbation of alphaB-crystallin by zinc and temperature related to its chaperone-like activity. Int J Biol Macromol 2007; 42:229-34. [PMID: 18048095 DOI: 10.1016/j.ijbiomac.2007.10.012] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2007] [Revised: 09/14/2007] [Accepted: 10/12/2007] [Indexed: 11/18/2022]
Abstract
alphaB-crystallin is a small heat shock protein that shows chaperone-like activity, as it protects the aggregation of denatured proteins. In this work, the possible relationships between structural characteristics and the biological activity of alphaB-crystallin were investigated on the native protein and on the protein undergoing the separate effects of metal ligation and temperature. The chaperone-like activity of alphaB-crystallin increased in the presence of zinc and when temperature was increased. By using fluorescent probes to monitor hydrophobic surfaces on alphaB-crystallin, it was found that exposed hydrophobic patches on the protein surface increased significantly both in the presence of zinc and when the temperature was raised from 25 to 37 degrees C. The zinc-induced increased exposure of lipophilic residues is in agreement with theoretical calculations performed on 3D-models of monomeric alphaB-crystallin, and may be significant to its increased biological activity.
Collapse
Affiliation(s)
- Alessio Coi
- Dipartimento di Scienze Farmaceutiche, Università di Pisa, Via Bonanno 6, 56126 Pisa, Italy.
| | | | | | | | | | | |
Collapse
|
19
|
Massarelli I, Coi A, Pietra D, Nofal FA, Biagi G, Giorgi I, Leonardi M, Fiamingo F, Bianucci AM. QSAR study on a novel series of 8-azaadenine analogues proposed as A1 adenosine receptor antagonists. Eur J Med Chem 2007; 43:114-21. [PMID: 17418915 DOI: 10.1016/j.ejmech.2007.02.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2006] [Accepted: 02/13/2007] [Indexed: 10/23/2022]
Abstract
8-Azaadenines have been recently proposed as a novel promising class of adenosine A1 receptor antagonists. A QSAR study on 45 derivatives, synthesized in our laboratory as antagonists for A1 receptor, is described here. The use of the CODESSA program allowed obtaining a quite simple equation capable of correlating the structural features of these ligands to their activity toward A1 receptor. The model was investigated for reliability and stability by using statistical analysis criteria stricter than usual. Particular care was put in defining the chemical space where the model gave reliable predictions. The model allowed the identification of relevant structural features required for the interaction with the A1 receptor, enabling the prediction of activity of molecules belonging to focused virtual libraries.
Collapse
Affiliation(s)
- Ilaria Massarelli
- Department of Chemistry and Industrial Chemistry, University of Pisa, via Risorgimento 35, 56126 Pisa, Italy
| | | | | | | | | | | | | | | | | |
Collapse
|
20
|
Massarelli I, Murgia L, Bianucci AM, Chiellini F, Chiellini E. Understanding the Selectivity Mechanism of the Human Asialoglycoprotein Receptor (ASGP-R) toward Gal- and Man-type Ligands for Predicting Interactions with Exogenous Sugars. Int J Mol Sci 2007. [PMCID: PMC3662984] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
A practical approach for addressing the computer simulation of protein-carbohydrate interactions is described here. An articulated computational protocol was set up and validated by checking its ability to predict experimental data, available in the literature, and concerning the selectivity shown by the Carbohydrate Recognition Domain (CRD) of the human asialoglycoprotein receptor (ASGP-R) toward Gal-type ligands. Some required features responsible for the interactions were identified. Subsequently the same protocol was applied to monomer sugar molecules that constitute the building blocks for alginates and ulvans. Such sugar polymers may supply a low-cost source of rare sugars with a potential impact on several industrial applications, from pharmaceutical to fine chemical industry. An example of their applicative exploitation could be given by their use in developing biomaterial with adhesion properties toward hepatocytes, through interaction with the ASGP-R. Such a receptor has been already proposed as a target for exogenous molecules, specifically in the case of hepatocytes, for diagnostic and therapeutic purposes. The DOCK5.2 program was used to search optimal locations of the above ligands of interest into CRD binding site and to roughly estimate interaction energies. Finally, the binding ΔG of theoretical protein-ligand complexes was estimated by using the DelPhi program in which the solvation free energy is accounted for with a continuum solvent model, by solving the Poisson-Boltzmann equation. The structure analysis of the obtained complexes and their ΔG values suggest that one of the sugar monomers of interest shows the desired characteristics.
Collapse
Affiliation(s)
- Ilaria Massarelli
- Dipartimento di Chimica e Chimica Industriale, Università di Pisa, Via Risorgimento 35, 56126 Pisa, Italy. E-mail: ; ; ;
| | - Laura Murgia
- Dipartimento di Chimica e Chimica Industriale, Università di Pisa, Via Risorgimento 35, 56126 Pisa, Italy. E-mail: ; ; ;
| | - Anna Maria Bianucci
- Dipartimento di Scienze Farmaceutiche, Università di Pisa, Via Bonanno 6, 56126 Pisa, Italy. E-mail:
| | - Federica Chiellini
- Dipartimento di Chimica e Chimica Industriale, Università di Pisa, Via Risorgimento 35, 56126 Pisa, Italy. E-mail: ; ; ;
| | - Emo Chiellini
- Dipartimento di Chimica e Chimica Industriale, Università di Pisa, Via Risorgimento 35, 56126 Pisa, Italy. E-mail: ; ; ; ,Author to whom correspondence should be addressed. E-Mail:
| |
Collapse
|
21
|
Giorgi I, Bianucci AM, Biagi G, Livi O, Scartoni V, Leonardi M, Pietra D, Coi A, Massarelli I, Nofal FA, Fiamingo FL, Anastasi P, Giannini G. Synthesis, biological activity and molecular modelling of new trisubstituted 8-azaadenines with high affinity for A1 adenosine receptors. Eur J Med Chem 2007; 42:1-9. [DOI: 10.1016/j.ejmech.2006.08.014] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2006] [Revised: 07/21/2006] [Accepted: 08/11/2006] [Indexed: 10/24/2022]
|
22
|
Coi A, Massarelli I, Murgia L, Saraceno M, Calderone V, Bianucci AM. Prediction of hERG potassium channel affinity by the CODESSA approach. Bioorg Med Chem 2006; 14:3153-9. [PMID: 16426850 DOI: 10.1016/j.bmc.2005.12.030] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2005] [Revised: 12/12/2005] [Accepted: 12/16/2005] [Indexed: 11/27/2022]
Abstract
The problem of predicting torsadogenic cardiotoxicity of drugs is afforded in this work. QSAR studies on a series of molecules, acting as hERG K+ channel blockers, were carried out for this purpose by using the CODESSA program. Molecules belonging to the analyzed dataset are characterized by different therapeutic targets and by high molecular diversity. The predictive power of the obtained models was estimated by means of rigorous validation criteria implying the use of highly diagnostic statistical parameters on the test set, other than the training set. Validation results obtained for a blind set, disjoined from the whole dataset initially considered, confirmed the predictive potency of the models proposed here, so suggesting that they are worth to be considered as a valuable tool for practical applications in predicting the blockade of hERG K+ channels.
Collapse
Affiliation(s)
- Alessio Coi
- Dipartimento di Scienze Farmaceutiche, Università di Pisa, Via Bonanno 6, 56126 Pisa, Italy
| | | | | | | | | | | |
Collapse
|
23
|
Coi A, Tonelli M, Ganadu ML, Bianucci AM. Binding free energy calculations of adenosine deaminase inhibitors. Bioorg Med Chem 2006; 14:2636-41. [PMID: 16376548 DOI: 10.1016/j.bmc.2005.11.047] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2005] [Revised: 11/16/2005] [Accepted: 11/22/2005] [Indexed: 10/25/2022]
Abstract
The interactions between four inhibitors and adenosine deaminase (ADA) were examined by calculating their binding free energies after molecular dynamics simulations. A bonded model was used to represent the electrostatic potentials of the zinc coordination site. The charge distribution of the model was derived by using a two-stage electrostatic potential fitting calculations. The calculated binding free energies are in good agreement with the experimental data and the ranking of binding affinities is well reproduced. Notably, our findings suggest that non-polar contributions play an important role for ADA-inhibitor interactions.
Collapse
Affiliation(s)
- Alessio Coi
- Dipartimento di Scienze Farmaceutiche, Università di Pisa, 56126 Pisa, Italy
| | | | | | | |
Collapse
|
24
|
Biagi G, Bianucci AM, Coi A, Costa B, Fabbrini L, Giorgi I, Livi O, Micco I, Pacchini F, Santini E, Leonardi M, Nofal FA, Salerni OL, Scartoni V. 2,9-disubstituted-N6-(arylcarbamoyl)-8-azaadenines as new selective A3 adenosine receptor antagonists: synthesis, biochemical and molecular modelling studies. Bioorg Med Chem 2005; 13:4679-93. [PMID: 15908217 DOI: 10.1016/j.bmc.2005.04.063] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2004] [Revised: 04/22/2005] [Accepted: 04/22/2005] [Indexed: 11/19/2022]
Abstract
A number of N6-(N-arylcarbamoyl)-2-substituted-9-benzyl-8-azaadenines, obtained by a modification of the synthetic scheme used to prepare selective A1 ligands, by only three or two steps, are described. At first we prepared a series of 2-phenyl-9-benzyl-8-azaadenines having as N6 substituent a variously substituted N-phenylcarbamoyl group. Some of these derivatives demonstrated good affinity towards the A3 subtype but low selectivity. Compounds having p-CF3, p-F and p-OCH3, as substituents on the phenylcarbamoyl group were selected as lead compounds for the second part of this study. Without modifying the N6 substituent, which would assure A3 affinity, we varied the 9 and 2 positions on these molecules to enhance selectivity. Some compounds having a p-methyl group on the 2-phenyl substituent showed a very good affinity and selectivity for the A3 subtype, revealing the first class of A3 adenosine receptor selective antagonists with a bicyclic structure strictly correlated to the adenine nucleus. The molecular modelling work, carried out using the DOCK program, supplied two models which may be useful for a better understanding of the binding modes. Both models highlighted the preferred interacting tautomeric forms of the antagonists for human A1 and A3 receptors.
Collapse
Affiliation(s)
- Giuliana Biagi
- Dipartimento di Scienze Farmaceutiche, Università di Pisa, via Bonanno 6, 56126 Pisa, Italy
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
25
|
Borghini A, Pietra D, Domenichelli P, Bianucci AM. QSAR study on thiazole and thiadiazole analogues as antagonists for the adenosine A1 and A3 receptors. Bioorg Med Chem 2005; 13:5330-7. [PMID: 15990318 DOI: 10.1016/j.bmc.2005.05.041] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2005] [Revised: 05/18/2005] [Accepted: 05/24/2005] [Indexed: 10/25/2022]
Abstract
Thiazole and thiadiazole analogues have been recently proposed as a novel promising class of adenosine A1 and A3 receptor antagonists. When appropriately modified, they show selectivity toward A1 or A3 receptors, which results in a variety of therapeutic potentialities of these ligands. In this work, we carried out a QSAR study on thiazole and thiadiazole analogues as antagonists for adenosine A1 and A3 receptors. To develop reliable models, we focused attention on any possible pitfalls of each step of QSAR process and approached each stage following accurate procedures. Application of datasets by using CODESSA software led to QSAR equations based on three and four descriptors for the adenosine A1 and A3 receptor ligands, respectively. The obtained models allowed us to understand the main structural features that strongly correlate with the target property.
Collapse
Affiliation(s)
- Alice Borghini
- Dipartimento di Scienze Farmaceutiche, Università di Pisa, Via Bonanno 6, 56126 Pisa, Italy
| | | | | | | |
Collapse
|
26
|
Coi A, Bianucci AM, Ganadu ML, Mura GM. A modeling study of αB-crystallin in complex with zinc for seeking of correlations between chaperone-like activity and exposure of hydrophobic surfaces. Int J Biol Macromol 2005; 36:208-14. [PMID: 16098576 DOI: 10.1016/j.ijbiomac.2005.06.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2004] [Revised: 06/10/2005] [Accepted: 06/10/2005] [Indexed: 11/26/2022]
Abstract
Three-dimensional models for alphaB-crystallin and its complex with zinc were obtained by molecular homology modeling and quantum mechanical calculations in order to explain the effect of the metal on the chaperone-like activity of alphaB-crystallin. In fact, measurements of the chaperone-like activity of alphaB-crystallin revealed that it is significantly increased in presence of the zinc. The theoretical models allowed us to estimate the increased exposition of hydrophobic residues caused by the presence of zinc, suggesting a relationship between structural changes and the increased chaperone-like activity.
Collapse
Affiliation(s)
- Alessio Coi
- Dipartimento di Chimica, Università degli Studi di Sassari, Via Vienna 2, 07100 Sassari, Italy
| | | | | | | |
Collapse
|
27
|
Testai L, Bianucci AM, Massarelli I, Breschi MC, Martinotti E, Calderone V. Torsadogenic Cardiotoxicity of Antipsychotic Drugs: a Structural Feature, Potentially Involved in the Interaction with Cardiac HERG Potassium Channels. Curr Med Chem 2004; 11:2691-706. [PMID: 15544470 DOI: 10.2174/0929867043364351] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Many non-cardiovascular drugs of common clinical use cause, as an unwanted accessory property, the prolongation of the cardiac repolarisation process, due to the block of the HERG (Human Ether-a-go-go Related Gene) potassium channel, responsible for the repolarising IKr current. This delayed cardiac repolarisation process can be often unmasked by a prolongation of the QT interval of the ECG. In these conditions, premature action potentials can generate morphologically anomalous after-polarisations, and trigger a dangerous kind of polymorphic ventricular tachyarrhythmia, known as torsade de pointes, which can evolve in ventricular fibrillation and death. The risk associated with the torsadogenic cardiotoxicity of drugs, which prolong the QT interval has been the topic of documents produced by many health authorities, giving important issues about the preclinical and clinical evaluation of cardiac safety. Besides, public and private research laboratories developed several experimental in vitro or in vivo strategies, aimed to an early recognition of the influence of a drug (or of a drugcandidate) on the HERG channel and / or on the cardiac repolarisation process. Also the identification of a possible pharmacophore model, common in all or at least in numerous torsadogenic drugs, could represent a first step for the development of useful in silico approaches, allowing a preliminary indication about the potential torsadogenic property of a given molecule. In this work, we described the electrophysiological basis of torsade de pointes and listed several pharmacological classes of torsadogenic drugs. Among them, we focused our attention on antipsychotics, with an accurate overview on the experimental and clinical reports about their torsadogenic properties. Moreover, a common structural feature exhibited by these drugs, despite of their remarkable chemical differences, is evidenced by a computational approach and is indicated as a possible “facilitating” requirement for their torsadogenic properties. Together with other remarks, coming from different computational studies, the individuation of a satisfactory “toxicophore” model could be greatly useful, for the theoretical prediction of torsadogenic properties of a given chemical moiety and for the design of new drugs devoid of such an undesired and potentially lethal side-effect.
Collapse
Affiliation(s)
- L Testai
- Dipartimento di Psichiatria, Neurobiologia, Farmacologia e Biotecnologie, Università degli Studi di Pisa, Via Bonanno, 6, I-56126 Pisa - Italy
| | | | | | | | | | | |
Collapse
|
28
|
Pomelli CS, Bianucci AM, Crotti P, Favero L. A DFT investigation of the addition reaction of monomeric lithium enolate derived from propiophenone to propene oxide: examination of the possible transition structures. J Org Chem 2004; 69:150-7. [PMID: 14703391 DOI: 10.1021/jo034587m] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The addition reaction of monomeric lithium enolate (Z)-1, derived from propiophenone, to propene oxide 2, was examined to clarify the exact geometry of the transition state (TS) involved in this type of reaction. The eight possible TSs and the corresponding pathways, four leading to syn gamma-hydroxy ketone (gamma-HK) 3 and four leading to anti gamma-HK 4, were compared, using the B3LYP/6-31+G(d)//B3LYP/6-31+G(d) theory level in vacuo and in the presence of the reaction solvent (toluene/hexane). In every case, the favored pathway involves a TS where the enolate C=C and the epoxide C-C are in a gauche relationship and where the Li(+) is stabilized by some C-C and C-H sigma bonds of epoxide 2.
Collapse
Affiliation(s)
- Christian Silvio Pomelli
- Dipartimento di Chimica e Chimica Industriale, Università di Pisa, Via Risorgimento 35, 56126 Pisa, Italy
| | | | | | | |
Collapse
|
29
|
Bianucci AM, Micheli A, Sperduti A, Starita A. A Novel Approach to QSPR/QSAR Based on Neural Networks for Structures. Soft Computing Approaches in Chemistry 2003. [DOI: 10.1007/978-3-540-36213-5_10] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
|
30
|
Micheli A, Sperduti A, Starita A, Bianucci AM. Analysis of the internal representations developed by neural networks for structures applied to quantitative structure--activity relationship studies of benzodiazepines. J Chem Inf Comput Sci 2001; 41:202-18. [PMID: 11206375 DOI: 10.1021/ci9903399] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
An application of recursive cascade correlation (CC) neural networks to quantitative structure-activity relationship (QSAR) studies is presented, with emphasis on the study of the internal representations developed by the neural networks. Recursive CC is a neural network model recently proposed for the processing of structured data. It allows the direct handling of chemical compounds as labeled ordered directed graphs, and constitutes a novel approach to QSAR. The adopted representation of molecular structure captures, in a quite general and flexible way, significant topological aspects and chemical functionalities for each specific class of molecules showing a particular chemical reactivity or biological activity. A class of 1,4-benzodiazepin-2-ones is analyzed by the proposed approach. It compares favorably versus the traditional QSAR treatment based on equations. To show the ability of the model in capturing most of the structural features that account for the biological activity, the internal representations developed by the networks are analyzed by principal component analysis. This analysis shows that the networks are able to discover relevant structural features just on the basis of the association between the molecular morphology and the target property (affinity).
Collapse
Affiliation(s)
- A Micheli
- Dipartimento di Informatica, Università di Pisa, Italy.
| | | | | | | |
Collapse
|
31
|
Abstract
The human hepatic Asialoglycoprotein Receptor (ASGP-R) consists of two different types of liver specific membrane glycoproteins that bind to terminal galactose and N-acetylgalactosamine residues of serum glycoproteins. The two different polypeptide chains are referred to as two receptor subunits, HH1 and HH2, which are both involved in the activity of the functional receptor. This receptor has served as a model for understanding receptor-mediated endocytosis and carbohydrate mediated recognition phenomena. Here models for the C-terminal extracellular region of both HH1 and HH2 subunit are presented. The standard homology building procedure was modified in order to make it suitable for the modeling problem at hand. The models for the extracellular regions of HH1 and HH2 were initially constructed by exploiting several fragments, belonging to proteins of known 3D structure, and showing high local sequence similarity with respect to the glycoproteins of interest. Putative binding sites were first hypothesized on the basis of the comparison with other complexes of lectins, the crystal structure of which was available in the Protein Data Bank. A model for the complex involving the HH2 subunit and the typical high affinity ligand N-acetylgalactosamine (NacGal) was refined as the first by a suitable combination of MD simulations and Energy Minimization calculations, since it seemed to quickly converge to a plausible structure. An intermediate model for HH1 was then rebuilt on the basis of the refined model for HH2. It was then submitted to a sequence of molecular dynamics simulations with templates which took into account the secondary structure prediction for a final refinement. The structures of small regions of the models, located around the binding sites, were compared with more recent crystallographic data regarding a complex involving the mutant of Mannose Binding Protein QPDWGH (1BCH entry in the Protein Data Bank) and NacGal. This mutant shows high local sequence similarity with HH1 and HH2 at the binding sites. On the basis of the above comparison, different locations of the binding sites were also considered. In addition to other expected interactions, two hydrophobic interactions were observed in the models with Trp residues (positions 243 in HH1 and 181 or 267 in HH2 respectively) and His residues (positions 256 in HHI and 184 in HH2.respectively). The quality of the models was evaluated by the Procheck program and they seemed plausible. This observation together with analogies found between binding sites of the models and IBCH supported the validity of the models. A further validation element arose by comparison between experimental binding data available in the literature about the homologous rat receptor subunits and theoretical interaction energies evaluated, by means of the DOCK 3.5 program, in models for the rat subunits obtained from the corresponding human ones. The new modeling procedure used here appears to be a well-suited method for structural analysis of small regions, located around the ligands, in proteins of unknown 3D structure.
Collapse
Affiliation(s)
- A M Bianucci
- Dipartimento di Scienze Farmaceutiche, Universita' di Pisa, Italy.
| | | |
Collapse
|
32
|
|
33
|
Tonelli M, Ragg E, Bianucci AM, Lesiak K, James TL. Nuclear magnetic resonance structure of d(GCATATGATAG). d(CTATCATATGC): a consensus sequence for promoters recognized by sigma K RNA polymerase. Biochemistry 1998; 37:11745-61. [PMID: 9718297 DOI: 10.1021/bi980481n] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The three-dimensional structure of d(GCATATGATAG).d(CTATCATATGC), from the promoter region of a gene regulating sporulation in Bacillus subtilis mother cells, was determined utilizing two-dimensional nuclear Overhauser effect (2D NOE) and double-quantum-filtered COSY (2QF-COSY) spectra. To minimize the effect of methods used to obtain restraints and refine structure, several variables were studied. Interproton distance bounds were calculated very conservatively by running the complete relaxation matrix program MARDIGRAS hundreds of times using 2D NOE spectra for exchangeable and for nonexchangeable protons at different mixing times, assuming different overall correlation times and different starting structures. The 435 distance restraints were used with two different structural refinement methods: restrained molecular dynamics (rMD) and restrained Monte Carlo calculations (rMC). Refinement using different procedures and starting structures resulted in essentially the same structure (<0.8 A rmsd), indicating that the structure is defined by experimental restraints and not the refinement method or variables used. R factors indicate the structures fit the experimental NOE data very well. Some helical parameters, notably large negative X displacement, are characteristic of A-DNA, but others are characteristic of B-DNA. As with TG.CA steps in other duplex DNA sequences studied in our laboratory, the two TG.CA steps have a positive roll, with T6-G7 exhibiting the largest, and consequently a bent helix axis. The converged structure represents a time-averaged structure. However, multiple conformations, especially in deoxyriboses, were evident from vicinal coupling constants obtained from quantitative simulations of 2QF-COSY cross-peaks and from persistent inconsistencies in experimental distances due to nonlinear conformational averaging.
Collapse
Affiliation(s)
- M Tonelli
- Department of Pharmaceutical Chemistry, University of California, San Francisco 94143-0446, USA
| | | | | | | | | |
Collapse
|
34
|
Bianucci AM, Bigi MU, Biagi G, Giorgi I, Livi O, Scartoni V. A 3D model of the human A1 adenosine receptor. An evaluation of the binding free-energy with ligands. Drug Des Discov 1998; 15:149-56. [PMID: 9689498] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
A model of A1 adenosine receptor was built on the basis of the prediction of transmembrane helices made by PHDtopology and forcing the rough initial model over the scaffold of the rhodopsin. Only helices were accurately modeled. Several complexes between the model of the A1 receptor and some ligands were built. The binding site was hypothesized on the basis of biochemical experiments (site directed mutagenesis). Ligands were selected so that their Kis range between millimolar to nanomolar. The validation of the model was carried out performing calculations of the binding free energy between ligands and the receptor model. The free energy calculations were accomplished by using the linear free energy approximation method (LIE). We could observe that the trend of the calculated delta delta Gs (differences in binding free energies between the antagonist 2, showing the lowest Ki, and the other antagonists analyzed) agreed with the one obtained from biological data.
Collapse
Affiliation(s)
- A M Bianucci
- Dipartimento di Scienze Farmaceutiche, Università di Pisa, Italy
| | | | | | | | | | | |
Collapse
|
35
|
Da Settimo A, Marini AM, Bianucci AM, Primofiore G, Da Settimo F, Boldrini E. Synthesis of 2-methylaminobenzimidazole derivatives tested for antiinflammatory activity. Farmaco 1994; 49:829-34. [PMID: 7893341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
A series of 1-alkyl substituted 2-methylaminobenzimidazole derivatives was prepared and tested. Some of them were assayed orally in the rat for antiinflammatory and analgesic properties. The compounds did not exhibit any significant activity compared with reference drug levels.
Collapse
Affiliation(s)
- A Da Settimo
- Dipartimento di Scienze Farmaceutiche, Università di Pisa, Pisa
| | | | | | | | | | | |
Collapse
|
36
|
Bianucci AM, Da Settimo A, Da Settimo F, Primofiore G, Martini C, Giannaccini G, Lucacchini A. Benzodiazepine receptor affinity and interaction of some N-(indol-3-ylglyoxylyl)amine derivatives. J Med Chem 1992; 35:2214-20. [PMID: 1319492 DOI: 10.1021/jm00090a011] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Several derivatives, in which tryptamine, tyramine, and dopamine moieties are linked to the indole nucleus by an oxalyl bridge, were tested for their ability to displace the specific binding of [3H]flunitrazepam from bovine brain membranes. GABA ratio and in vivo tests for the most potent compounds showed they behave as inverse agonists at the benzodiazepine receptor (BzR). To better define the structure-activity relationship (SAR) of this kind of ligand, several phenylethylamine derivatives were synthesized to evaluate their affinity to BzR. Some of these derivatives (17, 21, 24, 26, and 30) were found to exhibit high affinity (Ki = 0.51-0.085 microM) for BzR and possessed a partial agonist activity, although their chemical structure is closely related to tryptamine 2-6, tyramine 7-11, and dopamine 12-16 derivatives. A different interaction of these ligands to the receptor site is hypothesized. Moreover, all the prepared 1-methyl derivatives exhibited very low binding affinity to BzR.
Collapse
Affiliation(s)
- A M Bianucci
- Istituto di Chimica Farmaceutica, Università di Pisa, Italy
| | | | | | | | | | | | | |
Collapse
|
37
|
James TL, Borgias BA, Bianucci AM, Zhou N. Determination of DNA and protein structures in solution via complete relaxation matrix analysis of 2D NOE spectra. Basic Life Sci 1990; 56:135-54. [PMID: 2078169 DOI: 10.1007/978-1-4684-5868-8_9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- T L James
- Department of Pharmaceutical Chemistry, University of California, San Francisco 94143
| | | | | | | |
Collapse
|
38
|
Abstract
Phase-sensitive two-dimensional nuclear Overhauser effect spectra of [d(GGTATACC)]2 in aqueous deuterium oxide solution at four mixing times were quantified to give all nonoverlapping cross-peak intensities. A structural model for [d(GGTATACC)]2 was built in which the GG- and -CC moieties were in the B-DNA form, while the middle -TATA- moiety was in the wrinkled-D form (BDB model). This model was subjected to energy refinement by molecular mechanics calculations with the program AMBER. Counterions (Na+) were added to neutralize the charges, and water molecules were placed bridging across the minor groove. A complete relaxation matrix analysis was used to calculate two-dimensional nuclear Overhauser effect spectra of [d(GGTATACC)]2 from the above models (before and after energy refinement) and from four other [d(GGTATACC)]2 structural models: regular A, crystalline A, regular B, and energy-minimized B. Among them, the energy-minimized BDB model yielded a set of theoretical spectra that gave the best fit to the experimental spectra. It was also the energetically most stable. Therefore, it is a good representation of the ensemble- and time-averaged structure of the octamer in solution. This model has backbone torsion angles similar to those of B-form DNA in the GG- and -CC moieties and torsion angles similar to those of wrinkled D form DNA in the -TATA- moiety. The base stacking and base pairing are not interrupted at the junctions between the two structural moieties. Its minor groove is narrower than that of B DNA, and the solvent-accessible surface of the minor groove forms a closed hydration tunnel in the middle -TATA- segment.
Collapse
Affiliation(s)
- N Zhou
- Department of Pharmaceutical Chemistry, University of California, San Francisco 94143
| | | | | | | |
Collapse
|
39
|
Bianucci AM, Martinelli A, Da Settimo A. A conformational approach to histamine H2-receptor antagonists. Farmaco Sci 1984; 39:686-95. [PMID: 6148263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Four selective H2-antagonists were studied: burimamide, thiaburimamide, metiamide and cimetidine and their conformations were investigated using the PCILO method. The results show similar preferred conformations but also show that the most active drugs can more easily assume conformations different from the preferred ones. The selective H2-agonist dimaprit was also examined in order to find conformational features determining activity at the H2-histamine receptor.
Collapse
|