We have developed a new strategy for rapid restriction analysis and sorting of a large genomic library. Using this strategy, we have established a set of mutually overlapping lambda phage clones and the restriction map for eight six-base-recognizing enzymes that cover the whole of the 4700kb long genome of E. coli.
We discuss how the antigen binding site of immunoglobulin molecules is constructed in order to cope with the unlimited diversity of antigens. Importance of pattern recognition is emphasized for the antigen-antibody interactions. Relevance of the present idea to the general aspect of the specificity of molecular recognition by protein molecules is also discussed briefly.
A thick filament in skeletal muscle is a bipolar linear aggregate composed of hundreds of myosin molecules and accessory proteins such as C-protein. Recent studies have suggested that the "accumulated strain", mechanism plays an essential role in the length determination of thick filaments.
Microfilaments compose microvilli, fertilization cone, cortical layer, and contractile ring in sea urchin eggs, and microtubules compose sperm aster and mitotic apparatus. These cytoskeletal structures spatially and temporally change during fertilization and cleavage, which has become clear at molecular level using fluorescent analogues of actin and tubulin.
The signals which direct excision of infrons from mRNA precursors in higher eukaryotes' genes are not well understood. Although a consensus sequence, CA AG/GT AG AGT, has been proposed with the 5'-splice site actual 5'-splice site sequences differ from it to a greater or lesser degree. In the present paper, nucleotide sequences were transformed into categorical data, and quantification analysis developed by Hayashi was applied to such a system. Two classes of 5'-splice site sequences and sequences other than 5'-splice site were discriminated most distinctly. This approach was useful to know those factors which characterize 5'-splice signal sequences.
A fused enzyme of rat cytochrome P450c and rat NADPH-cytochrome P450 reductase was constructed by recombinant DNA technology. The fused enzyme produced in yeast cells showed P450c-dependent monooxygenase activity self-catalitically. The topological analysis of the fused enzyme suggested that in the yeast cell, the P450 moiety is embedded in the microsomal membrane protruding the reductase moeity to the cytoplasm.
Simple mathematical models of optimal copulation time, postocopulatory guarding, and precopulatory guarding of males, where the concept of an evolutionarily stable strategy (ESS) is used, are reviewed. The method by which these kinds of game theoretic problems can be solved is demonstrated, and parametic dependency of the optimal strategy is examiled. Actual observational and experimental examples are discussed in the light of predictions of the models.
The evolution of natal emigration is studied theoretically assuming exogamy. The model predicts that extremely sex-biased pattem of natal emigration should be evolved, and that less productive sex is to leave the natal troop. Observed patterns of natal dispersal in bird alld nammal species are discussed, in relation to the present model.
Bacteria can monitor the environmental changes, transduce the signals and regulate the expression of a set of genes to adapt their metabolism to the changes. Several representative mechanisms of these global regulatory systems are reviewed. Many pairs of regulatory proteins have been found to possess a high degree of homology in their primary structures, suggesting that there is a common mechanism for the global regulatory systems which respond to the environmental changes.
The radius of gyration, which is the most important structural parameter obtainable by small-angle X-ray scattering (SAXS), comprises the information of the inner structure of protein in solution as well as the bulk structure. The rough distribution of electron density is revealed by contrast variation measurement. Heavy atom labeling with contrast variation reveals the number of heavy atoms binding to the protein and the distribution of heavy atoms in the protein. In the case of the oligomeric protein, other than the radius of gyration of the whole molecule, the radius of gyration of a subunit and the distance between subunits are obtainable by SAXS. Some examples are also summarized.