Notable

The Faculty of 1000 is aWeb-based literature awareness tool published by BioMed Central. For more information visit www.facultyof1000.com. ACTIVATING PK B/AKT J. Yang et al., "Molecular mechanism for the regulation of protein kinase B/Akt by hydrophobic motif phosphorylation," Molecular Cell, 9:1227-40, 2002. "This contribution is important because it presents the crystal structure of the catalytic domain of Akt/protein kinase B and presents a molecular explanation for why phosphorylation of the hydrophobic motif stabilizes the conformation of AGC kinases. Specifically, the authors propose that phosphorylation of the hydrophobic motif orders the C helix to more favorably align residues for catalysis." --Alexandra Newton, University of California, San Diego, US ASSEMBLING POROUS SOLIDS C.J. Kuehl et al., "Coordination-driven self assembly: solids with bidirectional porosity," Journal of the American Chemical Society, 124:7266-7, June 26, 2002. "The authors show that a very large dipyridyl macrocycle self-assembles with Pt(II) ions to form a highly porous crystalline solid containing two types of channels perpendicular to one another. There is continuing interest in designing synthetic zeolites and 'nanoporous' solids. The current work provides an important new example of how the use of preformed macrocycles can serve as useful building blocks for the metal-directed assembly of porous solids." --Steven Zimmerman, University of Illinois, US SENSING NTP D.A. Schneider et al., "NTP-sensing by rRNA promoters in Escherichia coli is direct," Proceedings of the National Academy of Sciences, 99:8602-7, June 25, 2002. "The synthesis of ribosomes is tightly coupled to the growth conditions of the cell, especially in bacteria, but the basis for this has remained elusive. The Gourse group shows in this paper that the transcription of rRNA is exquisitely dependent on the available ATP and GTP of the cell, due to the specific features of transcription initiation of rRNA, in confirmation of previous in vitro studies. This sensitivity to ATP and GTP provides a tight coupling with translation, the major consumer of ATP and GTP in the cell, and thus provides a basis for considering the regulation of cell growth integrated over all of macromolecular synthesis." --Jonathan R. Warner, Albert Einstein College of Medicine, US CHAPERONING CHEMICAL ASSEMBLIES V. Paraschiv et al., "Molecular 'chaperones' guide the spontaneous formation of a 15-component hydrogen-bonded assembly," Journal of the American Chemical Society, 124:7638-9, June 26, 2002. "Although the formation of hydrogen-bonded assemblies is usually fast and under thermodynamic control, the authors have discovered a 15-component hydrogen-bonded assembly that only forms in the presence of a small molecule 'chaperone.' It is likely that the chaperone, a mimic of one of the assembling components, prevents the rapid formation of kinetically inert structures, yet binds weakly enough that it can ultimately be displaced. The results suggest that very complicated, large, and unusually stable assemblies may be obtainable provided the researcher can guide their formation through specific intermediates." --Steven Zimmerman, University of Illinois, US STUDYING DNA DAMAGE RESPONSE B.R. Williams et al., "A murine model of nijmegen breakage syndrome," Current Biology," 12:648-53, June 22, 2002. "A murine model of the human cancer predisposition syndrome, Nijmegen breakage syndrome (NBS), is described in this paper in which both copies of the NBS1 gene lack the BRCT domain of the gene. Cells taken from these mice are phenotypically identical to cells from NBS patients. Additional results presented in the paper indicate that ATM and the Mre11 complex, which contains Nbs1, are involved in an essential DNA damage response pathway, and that either ATM or the Mre11 complex acts as a hub at which additional components of the pathway can be assembled. These mice and cells derived from them should provide a useful model system in which to study the DNA damage response." --Stephen Jackson, University of Cambridge, UK FLY-CASTING MECHANISM B.A. Shoemaker et al., "Speeding molecular recognition by using the folding funnel: The fly-casting mechanism," Proceedings of the National Academy of sciences, 97:8868-73, Aug. 1, 2000. "A mechanism for ligand binding by natively unfolded proteins is proposed based on the energy-landscape theory of protein folding. It is found that, through this mechanism, binding of ligands can be enhanced if the protein is partially unfolded by increasing the capture radius for the ligand and then coupling folding to ligand docking. This so-called fly-casting mechanism of ligand binding is a beautiful theoretical treatment for the extreme case of the old idea that strong binding requires conformational flexibility in the protein." --Victor Munoz, University of Maryland, US VISUALIZING THYMOCYTE- STROMAL CONTACTS P. Bousso, et al, "Dynamics of thymocyte- stromal cell interactions visualized by two-photon microscopy," Science, 296:1876-80, June 7, 2002. "Two-photon microscopy has been used in thymic organ culture to visualize the cellular interactions in the thymus associated with positive selection. Reaggregated thymocyte/stromal cell cultures carrying different fluorochromes in the two cell types showed extensive contacts between stromal cells and thymocytes, which were dependent on congruence between the T cell receptor and a presented class I-restricted epitope on the stromal cells. Two distinct kinds of interactions were documented--rapid transient dynamic contacts and prolonged stable contacts. If both interactions were inductive, which could not be directly demonstrated, then both current models of T cell activation may be said to be represented in this system. Thymocytes seemed frequently to burrow inside stromal cells; perhaps this behavior is the origin of the thymic nurse-cell concept." --Jonathan Howard, Institut fur Genetik, Germany

Notable

Interested in reading more?

Become a Member of