Antibody catalysis of peptidyl-prolyl cis-trans isomerization in the folding of RNase T1

An antibody generated to an alpha-keto amide containing hapten 1 catalyzes the cis-trans isomerization of peptidyl-prolyl amide bonds in peptides and in the protein RNase T1. The antibody-catalyzed peptide isomerization reaction showed saturation kinetics for the cis-substrate, Suc-Ala-Ala-Pro-Phe-pNA, with a kcat/Km value of 883 s-1.M-1; the reaction was inhibited by the hapten analog 13 (Ki = 3. 0 +/- 0.4 microM). Refolding of denatured RNase T1 to its native conformation also was catalyzed by the antibody, with the antibody-catalyzed folding reaction inhibitable both by the hapten 1 and hapten analog 13. These results demonstrate that antibodies can catalyze conformational changes in protein structure, a transformation involved in many cellular processes.     

Fully parallel integrated CAM/RAM using preclassification to enablelarge capacities

Many applications would benefit from the availability of large-capacity content addressable memories (CAMs). However, while RAMs, EEPROMs, and other memory types achieve ever-increasing per-chip bit counts, CAMs show little promise of following suit, due primarily to an inherent difficulty in implementing two-dimensional decoding. The serialized operation of most proposed solutions is not acceptable in speed-sensitive environments. In response to the resulting need, this paper describes a fully-parallel (single-clock-cycle) CAM architecture that uses the concept of “preclassification” to realize a second dimension of decoding without compromising throughput. As is typically the case, each CAM entry is used as an index to additional data in a RAM. To achieve improved system integration, the preclassified CAM is merged into the same physical array as its target RAM, and both use the same core cells. Architecture and operation of the resulting novel memory are described, as are two critical-path circuits: the match-line pull-down and the multiple match resolver. The memory circuits, designed in 0.8 μm BiCMOS technology, may be employed in chips as large as 1 Mb, and simulations confirm 37 MHz operation for this capacity. To experimentally verify the feasibility of the architectural and circuit design, an 8 kb test chip was fabricated and found to be fully functional at clock speeds up to 59 MHz, with a power dissipation of 260 mW at 50 MHz     

Prolate spheroidal antennas in isotropic plasma media

The problems of a gap-excited finite-sized prolate spheroidal antenna, with and without a confocal prolate spheroidal vacuum sheath, operated in a uniform cold and in a uniform warm lossy plasma medium, have been considered by applying boundary value problem techniques. The dependence of the input admittance, the current distribution, and the radiation pattern, upon the collision frequency, the electron temperature, the length of the antenna, the length-to-radius ratio for the antenna, the ratio of the plasma frequency to the operating frequency, and the thickness of a vacuum sheath have been investigated. Admittance curves are given from which the input admittance of a finite linear antenna can be estimated for a wide range of operating conditions and length-to-radius ratios. Conductance and susceptance maxima, dependent upon the vacuum sheath thickness, have been observed when using the cold plasma model foromega < omega_{p}. When using the warm plasma model in conjunction with the boundary condition that the normal component of the fluid velocity is zero at the antenna surface and at the vacuum sheath surface, the radiation resistance of the antenna is increased significantly for the parameters considered.     

The Generalized Transform

Generalized transforms for decomposing a signal in terms of discrete orthogonal transformation are developed. General relationships for factoring the transform matrices into a product of sparse matrices are derived. Efficient algorithms for fast computation of these transforms is a consequence of these sparse matrices. The flow graphs and hence the sequence of computations are identical for all the transforms with only the multipliers as the variables for the different transforms.     

Contribution to the characterization of acetylated protein fractions of vicia faba in view of their functional properties

Whilst the emulsifying properties of the protein fraction of vicia faba are almost independent on the acetylation degree, the shear modulus of the gels produced by heat denaturation increases at first with increasing acetylation degree, decreases with further increase of the acetylation, and comes finally to zero for very high acetylation degrees. By changes of pH and by influence of added NaCl, CaCl₂, AlCl₃, and starch, the shear modulus of gels of acetylated protein fractions of vicia faba can be increased, by addition of sunflower oil it can be decreased. On the base of studies on the fraction profile and on the changes of the content of sulfhydryl and disulfide groups of the protein fractions of vicia faba and the corresponding gels in dependence on the acetylation degree, an interpretation of the results is given.     

MALDI matrices for biomolecular analysis based on functionalized carbon nanomaterials

When used in small molar ratios of matrix to analyte, derivatized fullerenes and single wall nanotubes are shown to be efficient matrices for matrix-assisted laser desorption/ionization (MALDI) mass spectrometry. The mixing of an acidic functionalized fullerene with a solution of bioanalyte, depositing a dried droplet, and irradiating with a pulsed nitrogen laser yields protonated or cationized molecular ions. Derivatized fullerenes could offer several advantages over conventional MALDI matrices: a high analyte ionization efficiency, a small molar ratios (less than 1) of matrix/analyte, and a broader optical absorption spectrum, which should obviate specific wavelength lasers for MALDI acquisitions. The major disadvantage to the use of fullerenes is the isobaric interference between matrix and analyte ions; however, it is overcome by using MALDI-ion mobility time-of-flight (IM-oTOF) mass spectrometry to preseparate carbon cluster ions from bioanalyte ions prior to TOF mass analysis. However, an alternative to the dried droplet preparation of fullerene MALDI samples is the aerosolization of matrix-analyte solutions (or slurries) followed by impacting the aerosol onto a stainless surface. We also demonstrate that the fullerene matrices can be used to acquire spectra from rat brain tissue.