Bibliothek

feed icon rss

Ihre E-Mail wurde erfolgreich gesendet. Bitte prüfen Sie Ihren Maileingang.

Leider ist ein Fehler beim E-Mail-Versand aufgetreten. Bitte versuchen Sie es erneut.

Vorgang fortführen?

Exportieren
  • 1
    Digitale Medien
    Digitale Medien
    s.l. : American Chemical Society
    The @journal of physical chemistry 〈Washington, DC〉 95 (1991), S. 9791-9794 
    Quelle: ACS Legacy Archives
    Thema: Chemie und Pharmazie , Physik
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 2
    ISSN: 1520-6904
    Quelle: ACS Legacy Archives
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 3
    Digitale Medien
    Digitale Medien
    s.l. : American Chemical Society
    The @journal of physical chemistry 〈Washington, DC〉 97 (1993), S. 9113-9119 
    Quelle: ACS Legacy Archives
    Thema: Chemie und Pharmazie , Physik
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 4
    Digitale Medien
    Digitale Medien
    s.l. : American Chemical Society
    The @journal of physical chemistry 〈Washington, DC〉 98 (1994), S. 2318-2324 
    Quelle: ACS Legacy Archives
    Thema: Chemie und Pharmazie , Physik
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 5
    Digitale Medien
    Digitale Medien
    Springer
    Theoretical chemistry accounts 103 (2000), S. 380-389 
    ISSN: 1432-2234
    Schlagwort(e): Key words: Constrained amino acids – Cyclopropane amino acids – Conformational study – Solvent effects on conformation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract. 1-Aminocyclopropanecarboxylic acid (Ac3c) is a constrained α amino acid residue that exhibits peculiar conformational characteristics. The aim of the present study is to provide a deeper understanding of these features to be used as guidance to decide when to choose Ac3c as a building block for the design of peptide and protein surrogates. The whole Ramachandran plot of the Ace-Ac3c-NCH3 dipeptide was investigated at the Hartree–Fock level using a 6-31G(d) basis set and the most favorable structures were assessed on this surface by energy minimization. These results were subsequently used as a reference to generate specific molecular mechanics parameters for Ac3c compatible with the parm94 set of the AMBER force field. The effect of water as a solvent on the conformational profile of the dipeptide was also assessed using the Miertus–Scrocco–Tomasi self-consistent reaction-field model at the Hartree–Fock level using a 6-31G(d) basis set and using the AM1 semiempirical method. The conformational profile of the Ac3c dipeptide can be characterized by two symmetric low-energy regions for values of φ around ±80° with a wide range of values for ψ ranging from −40 to 180°, with the lower areas located at low values of ψ. Solvent effects do not alter the features of the conformational map, but a shift of the two absolute minima to (φ, ψ) values near (±90°, 0°) can be observed. These results are in accord with all experimental evidence and with the known tendency of Ac3c to induce β-turn conformations in peptides.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 6
    ISSN: 1573-501X
    Schlagwort(e): 2 ; 5-piperazinedione ; acetylcholinesterase ; combinatorial library ; inhibition ; molecular modeling ; multiple parallelsynthesis ; selectivity ; solid phase
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The potentiation of central cholinergic activity has beenproposed as a therapeutic approach for improving cognitivefunction in patients with Alzheimer's disease. Increasingthe acetylcholine concentration in brain by modulatingacetylcholinesterase (AChE) activity is among the mostpromising strategies. We have used a combinatorial approachto identify different 2,5-piperazinediones (DKP) with AChEinhibitory activity. Our goal was to find inhibitorsexhibiting high AChE/BuChE (butyrylcholinesterase)selectivity, in order to reduce the undesirable sideeffects elicited by most of the inhibitors that have beendeveloped to date. Screening of a DKP library constructedon solid-phase using the multiple parallel synthesisformat, resulted in the identification of several compoundswith moderate efficacy on AChE. In particular, DKP-80had an IC50 = 2.2 μM with no significant inhibitoryactivity on BuChE. Moreover, estimated values of Clog P andlog BB for the most active compounds fulfilled thebioavailability requirements for enzyme inhibitors actingon the central nervous system. In order to understand theinhibitory properties of the ligand at the molecular level,molecular dynamics simulations were computed on DKP-80 complexed to AChE, and the most relevant bindinginteractions of this inhibitor to the active center of theenzyme were characterized. Overall the present resultsindicate that the DKP-based compounds identified are novelAChE inhibitors which may be considered likely leadcompounds for further development of drug candidatesagainst Alzheimer's disease.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 7
    Digitale Medien
    Digitale Medien
    Springer
    Journal of computer aided molecular design 12 (1998), S. 111-118 
    ISSN: 1573-4951
    Schlagwort(e): GPCR ; novo modeling ; rhodopsin ; transmembrane domains ; receptors
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The only information available at present about the structural features of G-protein-coupled receptors (GPCRs) comes from low resolution electron density maps of rhodopsin obtained from electron microscopy studies on 2D crystals. Despite their low resolution, maps can be used to extract information about transmembrane helix relative positions and their tilt. This information, together with a reliable algorithm to assess the residues involved in each of the membrane spanning regions, can be used to construct a 3D model of the transmembrane domains of rhodopsin at atomic resolution. In the present work, we describe an automated procedure applicable to generate such a model and, in general, to construct a 3D model of any given GPCR with the only assumption that it adopts the same helix arrangement as in rhodopsin. The present approach avoids uncertainties associated with other procedures available for constructing models of GPCRs based on a template, since sequence identity among GPCRs of different families in most of the cases is not significant. The steps involved in the construction of the model are: (i) locate the centers of the helices according to the low-resolution electron density map; (ii) compute the tilt of each helix based on the elliptical shape observed by each helix in the map; (iii) define a local coordinate system for each of the helices; (iv) bring them together in an antiparallel orientation; (v) rotate each helix through the helical axis in such a way that its hydrophobic moment points in the same direction of the bisector formed between three consecutive helices in the bundle; (vi) rotate each helix through an axis perpendicular to the helical one to assign a proper tilt; and (vii) translate each helix to its center deduced from the projection map.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 8
    Digitale Medien
    Digitale Medien
    Springer
    Journal of computer aided molecular design 7 (1993), S. 241-250 
    ISSN: 1573-4951
    Schlagwort(e): Polyglycine II ; Packing effects ; Conformational study ; Hydrogen bond ; AM1
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary In order to get insight into the conditions that make polyglycine (PG)II a stable structure, the conformational features of three model molecules closely related to the PGII conformation were investigated. The model molecules selected were glycine dipeptide (AGN), glycine tripeptide (AGGN), and glycine tetrapeptide (AGGGN). Environmental effects were mimicked by means of formaldehyde molecules. The calculations were carried out at the SCF semiempirical level, using the AM1 method. The calculations show that of the three systems considered, only the AGGGN molecule presents a minimum energy conformation which corresponds to a PGII structure. The environmental conditions in which this conformation is found were also analyzed.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 9
    Digitale Medien
    Digitale Medien
    Springer
    Journal of computer aided molecular design 6 (1992), S. 175-190 
    ISSN: 1573-4951
    Schlagwort(e): Met-enkephalin ; Conformation ; Solvent effects ; Conformational search
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary An extensive exploration of the conformational hypersurface of Met-enkephalin has been carried out, in order to characterize different low-energy conformational domains accessible to this pentapeptide. The search strategy used consisted of two steps. First, systematic nested rotations were performed using the ECEPP potential. Ninety-two low-energy structures were found and minimized using the CHARMm potential. High and low-temperature molecular dynamics trajectories were then computed for the lowest energy structures in an iterative fashion until no lower energy conformers could be found. The same search strategy was used in these studies simulating three different environments, a distance-dependent dielectric ɛ=r, and two constant dielectrics ɛ=10 and ɛ=80. The lowest energy structure found in a distance-dependent dielectric is a Gly-Gly β-II′-type turn. All other structures found for ɛ=r within 10 kcal/mol of this lowest energy structure are also bends. In the more polar environments, the density of conformational states is significantly larger compared to the apolar media. Moreover, fewer hydrogen bonds are formed in the more polar environments, which increases the flexibility of the peptide and results in less structured conformers. Comparisons are made with previous calculations and experimental results.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 10
    Digitale Medien
    Digitale Medien
    Springer
    Journal of computer aided molecular design 12 (1998), S. 7-14 
    ISSN: 1573-4951
    Schlagwort(e): bioactive conformation ; conformational analysis ; Peptide T ; Peptide T analogs
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The conformational profiles of Peptide T, (5–8)Peptide T, [Abu5](4–8)Peptide T and (4–8)Peptide T were computed independently to assess the geometrical characteristics of the bioactive conformation of Peptide T. The conformational profiles of the peptides were computed within the molecular mechanics framework using an effective dielectric constant of 80. The conformational space was thoroughly sampled using an iterative simulated annealing protocol. The bioactive conformation was assessed by pairwise cross comparisons of each of the unique low energy conformations found for each of the different analogs studied. After a putative bioactive conformation was selected, in order to further validate our hypothesis the conformational profile of the potent compound cyclo(Thr-Thr-Asn-Tyr-Thr-Asp) was computed and the putative bioactive conformation was found. The conformation exhibits a pseudo β-turn involving the side chain of Thr5 and the carbonyl oxygen of Tyr7 forming a C12 ring.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
Schließen ⊗
Diese Webseite nutzt Cookies und das Analyse-Tool Matomo. Weitere Informationen finden Sie hier...