摘要:

AbstractThe binding mode of azide to the ferric form ofAplysia limacinamyoglobin has been studied by X‐ray crystallography. The three‐dimensional structure of the complex has been refined at 1.9 Å resolution to a crystallographicR‐factor of 13.9%, including 126 ordered solvent molecules. Azide binds to the heme iron, at the sixth co‐ordination position, and is oriented towards the outer part of the distal site crevice. This orientation is stabilized by an ionic interaction with the side‐chain if Arg66 (E10) which, form an outer orientation in the ‘aquo‐met’ ligand‐free myoglobin, folds back towards the distal site in the presence of the anionic ligand. In the absence of a hydrogen bond donor residue at the distal E7 position inAplysia limacinamyoglobin, a different polar residue, Arg66 at the E10 topological position, has been selected by molecular evolution in order to grant li

ISSN:0952-3499    

DOI:10.1002/jmr.300040102

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

AbstractThe ligand binding site of a monoclonal antibody (185), which binds the neuroleptic drug haloperidol, has been modelled using canonical structures and energy minimization techniques. This refined modelling protocol has allowed us to predict the variable region loop conformation. Three key residues, H:50(W), H:100a(D) and L:96(Y) appear to create the basis of the electrostatic, π–π stacking interactions and hydrogen bonding required for the high affinity binding site characteristics present in this antibody. The use of computer‐aided graphics techniques and appropriate three‐dimensional modelling permits inspection of the predicted molecular recognition features of the ligand bindi

ISSN:0952-3499    

DOI:10.1002/jmr.300040103

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

AbstractWe present a homology scanning microcomputer program to predict functional T‐cell epitopes within proteins. By taking into account particular human or mouse restriction elements the predictions are made haplotype‐sepecific. The generality of this approach is confirmed by (i) identification of well‐characterized immunogenic T‐cell determinants in lysozyme (ii) search for potential T epitopes on unanalysed proteins like the human β2‐adrenoreceptor (iii) modification of non‐immunogenic peptide sequences in order to generate T‐cel

ISSN:0952-3499    

DOI:10.1002/jmr.300040104

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

AbstractTo specify electron exchanges involvingDesulfovibrio desulfuricansNorway tetra‐heme cytochromec3, the chemical modification of arginine 73 residue performed. Biochemical and biophysical studies have shown that modified cytochrome retains its ability to both interact and act as an electron carrier with its redox partners, ferredoxin and hydrogenase. Moreover, the chemical modification effects on the cytochromec31H NMR spectrum were similar to that induced by the presence of ferredoxin. This suggests that arginine 73 is localized on the cytochromec3ferredoxin interacting site. The identification of heme 4, the closest heme to arginine 73, as the ferredoxin interacting heme helps us to hypothesize about the role of three other hemes in the molecule. A structural hypothesis for an intramolecular electron transfer pathway, involving hemes 4, 3, and 1, is proposed on th basis of the crystal structures ofD. vulgarisMiyazaki andD. desulfuricansNorway cytochromesc3. The unique of role of some structural features (α helix, aromatic residues) intervening between the heme groups, is propos

ISSN:0952-3499    

DOI:10.1002/jmr.300040105

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

AbstractEnkephalin molecules were bound to poly(Lys) (poly‐K) or poly(Ala‐Lys‐Ala‐Leu) (poly‐A) and their interactions with NG108‐15 cells, platelets, erythrocytes and fibroblast cells were investigated. A fluorescent probe, rhodamine, also was bound to the conjugates for monitoring interactions with these cells. Observations by fluorescence microscopy revealed that NG108‐15 cells, and fibroblast cells were labelled by the conjugates, whereas erythrocytes were not. Since polypeptides without enkephalin moieties were only weakly adsorbed on the cells, it was concluded that the enkephalin/polypeptide conjugates were bound specifically to receptors on the cells membrane. Interestingly, when the enkephalin/poly‐K conjugate was bound to NG108‐15 and fibroblast cells, fluorescent patches appeared on the membrane. Such patch formation was not clearly observed with an enkephalin/rhodamine or enkephalin/poly‐A conjugate. In the case of fibroblast cells, the fluorescence converged to a large cluster, which was ultimately internalized. The results suggest that clustering of the receptors in cell membranes in influenced by the carrier polymer presumably due to cross‐linking of the receptors and/or the effect of the

ISSN:0952-3499    

DOI:10.1002/jmr.300040106

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

ISSN:0952-3499    

DOI:10.1002/jmr.300040107

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

ISSN:0952-3499    

DOI:10.1002/jmr.300040101

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY