Definition of optimal substrate recognition motifs of Ca2+-calmodulin-dependent protein kinases IV and II reveals shared and distinctive features

The substrate recognition determinants of Ca2+-calmodulin-dependent protein kinase (CaMK) IV and CaMKIIalpha were investigated using peptide substrates modeled on the amino acid sequence encompassing Ser-9 of synapsin I. For both kinases, hydrophobic residues (Leu or Phe) at the -5 position, are well tolerated, whereas non-hydrophobic residues (Arg, Ala, or Asp) decrease Vmax/Km by 55- to >4000-fold. At the -3 position, substitution of Ala for Arg leads to decreases of 99- and 343- fold in Vmax/Km for CaMKIV and CaMKIIalpha, respectively. For both kinases, the nature of the residues occupying the -4, -1, and + 4 positions exerts relatively little influence on phosphorylation kinetics. CaMKIV and CaMKIIalpha respond differently to substitutions at the -2 and +1 positions. Substitution of Arg at the -2 position with non-basic residues (Gln or Ala) leads to 6-fold decreases in Vmax/Km for CaMKIV, but 17-28-fold increases for CaMKIIalpha. Additionally, peptides containing Leu, Asp, or Ala at the +1 position are phosphorylated with similar efficiencies by CaMKIV, whereas the Leu-substituted peptide is preferred by CaMKIIalpha (by a factor of 5.8-9.7-fold). Thus, CaMKIV and CaMKIIalpha preferentially phosphorylate substrates with the motifs: Hyd-X-Arg-X-X-Ser*/Thr*, and Hyd-X-Arg-NB-X-Ser*/Thr*-Hyd, respectively, where Hyd represents a hydrophobic, X any, and NB a non-basic amino acid residue. The different specificities of the two kinases may contribute to their targeting to distinct physiological substrates during Ca2+-dependent cellular events.     

Comments on "On some bounds in the algebraic Riccati and Lyapunov equations"

Results presented by Moil in the paper, which give some bounds for the trace and the determinant of the positive definite solution to the algebraic Riccati matrix equation, are shown to be erroneous, and suggestions to remedy these errors are made.     

New dyes containing the 1,3-benzodithiole residue

The synthesis of various compounds containing the 1,3-benzodithiole residue is reported. The compounds are examined for application as functional dyes for carbonless duplicating systems and are found to develop slowly on silica gel, and to have good fastness to light. Especially useful was 1,1-bis(p-dimethylaminophenyl)-2-(1',3'-benzodithiol-2'-yl)ethylene (5), which developed blue on silica gel; the developing rate and fastness properties of this derivative are compared with those of benzoyl leuco Methylene Blue.     

Binding of a phosphoprotein to the 3' untranslated region of the mouse protamine 2 mRNA temporally represses its translation

The synthesis of the protamines, the predominant nuclear proteins of mammalian spermatozoa, is regulated during germ cell development by mRNA storage for about 7 days in the cytoplasm of differentiating spermatids. Two highly conserved sequences, the Y and H elements present in the 3' untranslated regions (UTRs) of all known mammalian protamine mRNAs, form RNA-protein complexes and specifically bind a protein of 18 kDa. Here, we show that translation of fusion mRNAs was markedly repressed in reticulocyte lysates supplemented with a mouse testis extract enriched for the 18-kDa protein when the mRNAs contained the 3' UTR of mouse protamine 2 (mP2) or the Y and H elements of mP2. No significant decrease was seen when the fusion mRNAs contained the 3' UTR of human growth hormone. The 18-kDa protein is developmentally regulated in male germ cells, requires phosphorylation for RNA binding, and is found in the ribonucleoprotein particle fractions of a testicular postmitochondrial supernatant. We propose that a phosphorylated 18-kDa protein plays a primary role in repressing translation of mP2 mRNA by interaction with the highly conserved Y and H elements. At a later stage of male gamete differentiation, the 18-kDa protein no longer binds to the mRNA, likely as a result of dephosphorylation, enabling the protamine mRNA to be translated.     

Implementation of a RISC microprocessor for programmable logic controllers

A special purpose RISC (reduced instruction set computer) microprocessor for programmable logic controllers (PLC), named PLCRISC, is proposed. To develop an optimal PLCRISC, we analysed existing PLC programs currently used in factories, with special attention to the instruction execution characteristics and features required for a high performance PLC processor. Based on this analysis, an optimal RISC-style instruction set and an architecture suitable for the required features are suggested. In particular, the instruction format, the instruction pipeline, and the detailed internal architecture are the significant characteristics of the proposed PLCRISC. The performance enhancement achieved with a PLCRISC is seen from a straightforward evaluation. ASIC implementation with VHDL is also discussed. The PLCRISC is under fabrication in a 0.8 μm CMOS technology.     

Removal of hot spot speckle on rear projection screen using the rotating screen system

This paper investigates a method to remove hot spot speckle, which is produced by laser-long coherence, on a projection screen. The objective of the work has been to first create an image from a digital light processing (DLP) display system using an RGB laser source. We then successfully obtained a high-quality image with speckle contrast, which is less than 2% when the screen was rotated by piezoelectric motor.     

LQG/LTR methods for linear systems with delay in state

The LQG/LTR (linear quadratic Gaussian/loop transfer recovery) method is discussed, along with related frequency-domain properties for linear systems with delay in state. Based on the frequency-domain inequality and a robust stability condition, the guaranteed stability margin of LQ regulators and the guaranteed nondivergence margin of Kalman filters are obtained. To improve the robustness of LQG regulators, the asymptotic property of the filter gain is investigated and a loop-transfer recovery procedure is suggested with an illustration     

Diffusion of zinc into gaas through Al0.3Ga00.7As

The diffusion of zinc into GaAs, Al_0.3Ga_0.7As and Al_0.3Ga_0.7As/GaAs single heterostructures have been studied. The depth of the diffusion front is found to be proportional to the square root of the diffusion time, [t]^1/2, and for single heterostructures the Al_0.3Ga_0.7As layer thickness,d ₁ modifies this relationship through decreasing the junction depth byd ₁ multiplied by a constant. It is shown that this relationship can be used for predicting diffusion fronts in double heterostructures.