Vbbrational transition probabilities of Phillips system of C2 molecules are calculated on the assumption that potential energy curves are approximated by the Morse potential. As 9 upper levels and 5 lower levels of the system have been observed in the laboratory by Ballik and Ramsay (1963), the transition probabilities are calculated for 9×5=45 bands.
α-Lactalbumin and c-type lysozyme have quite different functions but their protein structures and gene organizations are very homologous. The exon 2 coding region of hen egg-white lysozyme contains most of amino acid residues comprising its active site cleft. We engineered a hybrid protein in which the exon 2 coding region of goat α-lactalbumin was replaced with that of hen lysozyme. This provided catalytic activity to α-lactalbumin.
The amino acid sequences of the 217 different Immunoglobulin (Ig)-like domains from 78 known members of the Ig family were compared for the four highly conserved segments and the frequencies of occurrence of amino acids at each position of the four segments were obtained as an amino acid versus position matrix. Using the frequency matrix as a probe, further Ig-related sequences were screened in NBRF database. It was found that trk and trkB proto-oncogene products, now known as receptors for neurotrophic factors, have two tandem repeats of the Ig-like domain in the extracellular region. Thus both trk and trkB are new members of the Ig family and they share structural similarity with a group of growth factor receptors with Ig-like domains in the extracellular region and protein tyrosine kinase in the intracellular region.
The eyeless Nanjo is a mutation that was found in a natural population of Drosophila melanogaster. Genetic analysis of this mutant revealed the following characteristics of this mutation. (1) The homozygous eyelessness is caused by a single recessive mutation which prevents the normal development of compound eyes. (2) An extremely variable morphological eye phenotype was generated by the introduction of a different genetic background to this mutant. (3) The estimated germ line reversion rate was very high. These results suggest that an extremely variable morphological eye phenotype might result from spontaneous somatic excision of some kind of a transposable element.
A cloned chromosomal DNA fragment of clover proliferation mycoplasmalike organism (MLO) was sequenced and used to synthesize biotinylated single-stranded DNA probes by asymmetric polymerase chain reaction. The biotinylated single-stranded DNA was identified by temperature gradient gel electrophoresis. Hand sections were prepared from tissues of periwinkle plants (Catharanthus roseus (L.) G. Don) individually inoculated with clover proliferation MLO or potato witches'-broom MLO. In situ hybridization of the sections with the biotinylated probes showed that clover proliferation MLO and potato witches'-broom MLO were located mainly in sieve tube elements. Western aster yellows MLO was not detected by in situ hybridization with the same biotinylated probes. MLO was detected first in the external phloem tissue and then in the internal phloem tissue as plants grew older. This investigation provides the first example of developing PCR-generated small biotinylated single-stranded DNA to trace the colonization of MLOs in plant tissues.
A specific binding protein to Joro spider toxin (JSTX) was isolated from the membranous fraction of bovine brain. The protein shows a molecular weight approximately 60±2K by SDS-PAGE and possesses a high affinity for JSTX. The possible role of the inhibitory action of JSTX may involve Ca dynamics in synaptic transmi ssion by NMDA, since the toxin selectively inhibits NMDA-derived Ca elevation in cultured hippocampal cells, and the amino acid sequence of the N-terminal portion of the toxin binding protein is homologous to calreticulin.
Proteinase A from Aspergillus niger var. macrosporus is a non-pepsintype acid proteinase, whose catalytic site and enzymatic mechanism remain to be clarified. As the first step toward elucidating its three-dimensional structure by X-ray crystallography, proteinase A was crystallized in ammonium sulfate solutions by the hanging-drop vapor diffusion method. In the absence of an organic solvent, only the aggregates of long, thin needles were formed. On the other hand, thicker rodlike single crystals were grown at around pH 1.75 when dimethylsulfoxide (DMSO) was added to a concentration of around 5%. The single crystals of proteinase A thus obtained were suitable for X-ray diffraction measurements with a precession camera.