Proline cluster

Beesley, T.E., Scott, R.P.W., Chiral Chromatography. Wiley, New York, 1999. Leavell, M.D., Gaucher, S.P., Leary, J.A., Taraszka, J.A., Clemmer, D.E., Conformational studies of Zn-ligand-hexose diastereomers using ion mobility measurements and density functional theory calculations. J. Am. Soc. Mass Spectrom. 2002, 13, 284. Myung, S., Fioroni, M., Julian, R.R., Koeniger, S.L., Baik, M.H., Clemmer, D.E., Chirally directed formation of nanometer-scale proline clusters. J. Am. Chem. Soc. 2006, 128, 10833. 

Fak (focal adhesion kinase) is expressed in most tissues and is evolutionary conserved across species. It is activated by integrin clustering and by stimulation of several G protein-coupled recqrtors and RTKs. Fak is associated with focal adhesions and regulates cell spreading and migration. The kinase is essential for embryonic development since the homozygote Fak knockout is embryonic lethal. Pyk2 (proline-rich tyrosine kinase 2), the second member of the Fak kinase family has a more restricted expression pattern (primarily neuronal and hematopoietic cells) and does not localize to focal adhesions. 

The 3D crystal structure of Dsm. baculatum [NiSeFe] hydrogenase has been solved 185), and it was indicated that the enzyme contains three [4Fe-4S] centers. A cysteine (replacing a proline usually found near the [3Fe-4S] core) provides an extra ligand, enabling the acceptance of a fourth iron site at this cluster. 

The transmembrane domain in the RPTK is a hydrophobic segment of 22-26 amino acids inserted in the cell membrane. It is flanked by a proline-rich region in the N-terminus and a cluster of basic amino acids in the C-ter-minus. This combination of structures secures the transmembrane domain within the lipid bilayer. There is a low degree of homology in the transmembrane domain, even between two closely related RPTKs, suggesting that the primary sequence contains little information for signal transduction. 

Isomer shift data, Fe,S4 clusters, 38 20, 50 Isomorphic substitution, 39 179, 186 p-Isonicotinamide complexes, osmium, 37 307 p-lsonicotinamidepoly(proline) complexes, osmium, 37 307 Isonitrile complexes osmium, 37 245 technetium(I), 41 13-14 technetium(II), 41 31 technetium(IIl), 41 45 Isopolymolybdates, 19 239ff 19 265-280 crystallization from aqueous solution, 19 265-269... 

By carefully adjusting the distances between two sialoside residues in a number of divalent clusters. Click and Knowles [105] have obtained dimer 104 having the two sialic acid 5.7 nm apart. Compound 104 was 100-fold more potent than methyl a-sialoside (Neu5Aca2Me) in influenza virus inhibitions and 500-fold more potent in the case of polyomia virus. Alternatively, sialyl-a-(2,6)-/3-LacNAc dimers (105) branched at different positions of synthetic peptides, including compact glycine-rich and helical proline-rich peptides, afforded clusters which were only 8- and 4-fold more potent, respectively, than the corresponding monovalent trisaccharide [106]. 

Iron-sulfur clusters are important co-factors in electron-transfer. Type I reaction centres contain [4Fe-4S] clusters as final electron acceptors mediating ET to soluble electron carriers like ferredoxin or flavodoxin (reviewed in references 188, 224, 314, 315) In PS I three clusters (F FA and FB) have been clearly identified and spectroscopically characterized. The PsaA and PsaB subunits carry most of the ET cofactors in PS I.18178-316 Each of them provides two Cys ligands to the binding site of the interpolypeptide [4Fe-4S] cluster Fx. This binding site is identical on both core PS I subunits.317 Both [4Fe-4S] clusters FA and Fb are bound to the PS I stromal subunit PsaC. It contains two identical [4Fe-4S] consensus binding sites CxxCxxCxxxCP (C = cysteine, P = proline). 

Two types of crosslinking domains exist in tropoelastin those rich in alanine (KA) and those rich in proline (KP). Within the KA domains, lysine residues are typically found in clusters of two or three amino acids, separated by two or three alanine residues. These regions are proposed to be Q-helical with 3.6 residues per turn of helix, which has the effect of positioning two lysine sidechains on the same side of the helix, although there is no direct structural evidence (Brown-Augsburger et al., 1995 Sandberg et al, 1971), and facilitating the formation of desmosine crosslinks. Desmosine crosslinks are formed by the condensation of two allysine... 

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