Self-assembly of alpha-helical coiled coil nanofibers

The alpha-helical coiled coil is one of the best-studied and most well-understood protein folding motifs. In particular, the coiled coil can be made to self-assemble into a nanofibrous architecture with many potential applications in biomimetic engineering and elsewhere. The key to the assembly of such nanofibers has been the formation of "sticky ended" dimers through careful selection of electrostatically charged amino acids. In this work, we demonstrate for the first time that sticky ended dimers are not a prerequisite for alpha-helical coiled coil nanofiber formation. In contrast, we show that blunt-ended dimers are able to form nanofibers with a uniform diameter of 4 nm while being hundreds of nanometers in length. Furthermore, the length and lateral packing can be controlled through selection of amino acids not involved in the coiled coil interface.     

A new method for the synthesis of 5-amidinobarbiturates

The reactions of 5-[arylamino(methylthio)methylene]pyrimidine-2,4,6(1H,3H,5H)-triones with different aliphatic and aromatic amines were studied. A series of 5-amidinobarbiturates was synthesized. A new and preparatively convenient method for their synthesis appropriate for the use in the combinatorial chemistry was developed. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1557–1563, August, 2007.     

Ozonides of perfluorooct-1-ene and perfluorooct-2-ene

Ozonides of higher perfluoroalkenes were prepared for the first time by ozonation of perfluorooct-1-and-2-enes in Freon-113. The structures of the resulting compounds were confirmed by¹³C NMR spectroscopy and GLC-mass spectrometry.     

NR activity in the accelerating cavities development and study for ILC positron source parameters

The critical part of the normal conducting (NC) positron preaccelerator (PPA) at the ILC positron source (PS) are capture sections that should operate with an accelerating gradient of up to 15 MV/m in combination with long RF pulse (∼1 ms). Developed at the Institute of Nuclear Research (INR) and now being constructed at DESY, the CDS booster cavity for the Photo Injector Test facility, DESY, Zeuthen, will operate under the same conditions and is a full-scale, high-RF-power prototype of the PS capture cavities. Cavity construction status and results of cavity tuning at a low RF level are presented. Other features of the standing wave cavities for the PPA, such as RF pulsed heating, advanced cooling, and beam loading, are discussed. The text was submitted by the authors in English.