Anti-NCR2 monoclonal antibody, clone 9G23

We have carried out a combined density functional theory and molecular mechanics study of aryl group transfer reactions from [MeB(C6F5)(3)](-) to the metal center of L2MMe+ (M = Ti, Zr). This reaction, which produces L2MMe(C6F5) and MeB(C6F5)(2), is a possible deactivation pathway in metal-catalyzed single-site olefin polymerization. The cationic catalyst systems L2MMe+ include (NPR3)(2)MMe+, (Cp)(NPR3)MMe+, (Cp)(NCR2)MMe+, (CP)(SiMe2NR)MMe+, and (Cp)(OSiR3)MMe+. With M = Ti and Zr, the results show that aryl group transfer is more facile for zirconium catalysts than for the corresponding titanium systems. Furthermore, electron-donating ligands and sterically demanding substituents play a crucial role in preventing the aryl transfer reaction. The aryl group transfer is likely to take place for (Cp)(NCR2)MMe+ with both titanium- and zirconium-ketimide complexes at about 100 degreesC. However, the decomposition temperature is raised to 250 degreesC for the corresponding (Cp*)(NCR2)TiMe+ system.

Our previous studies[1] have identified that there are at least three regulatory regions (two negative regions and one positive region) in the 5'-flanking sequence of human beta-globin gene (-610 to +1 bp). The binding of HMG proteins to both negative regulatory regions was examined by the gel mobility shift and DNase I protection assays. In gel mobility shift assay, we observed that HMG proteins 1 and 2 could bind to both negative regulatory regions (NCR1 and NCR2). Using the gel shift competition assay, we identified that the binding proteins between the two regions are different from each other. DNase I protection analysis shows that HMG proteins 1 and 2 only bind to one site (between -560 and -533 bp) in NCR1. However, two protected regions can be detected in NCR2, one between -272 and -252 bp relative to the cap site, the other between -306 and -329 bp. We also observed that HMG proteins 14 and 17 could not bind to both negative regions, so it seems that HMG proteins 1 and 2 may play an important role in the regulation of beta-globin expression through DNA-protein interaction or through protein-protein interaction.