Isolation of the arginine repressor in Escherichia coli.
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Arginine↗
Biomedical subjects
S Udaka
Publications and source records attributed to S Udaka.
Pathway-specific pattern of control of arginine biosynthesis in bacteria.
Udaka, Shigezo (The Institute of Physical and Chemical Research, Komagome, Bunkyo-ku, Tokyo, Japan). Pathway-specific pattern of control of arginine biosynthesis in bacteria. J. Bacteriol. 91:617-621. 1966.-To compare control mechanisms of arginine biosynthesis in various bacteria, activities of several enzymes of the arginine pathway were measured in cells cultivated under repressed and partially derepressed conditions. Nineteen strains of bacteria tested appeared to have two types of pathways, closely related to each other. The partially derepressed levels of enzymes varied from bacterium to bacterium. The degree of inhibition of enzyme 2 (the second of eight enzymes concerned with arginine biosynthesis) and the repressibility of enzymes by arginine also appeared to vary from species to species. On the other hand, enzyme 2 was found to be the site of end-product inhibition only in the bacteria having a particular pathway. These results suggest that the bacteria have their own species-specific control mechanisms and that there is a pathway-specific pattern of control in arginine biosynthesis. The implications of the results are discussed from the viewpoint of evolution of control mechanisms.
Arginine↗
Protein secretion in Bacillus brevis.
Many strains of Bacillus brevis were isolated from nature as very efficient producers of extracellular proteins. Strains identified as B. brevis including these protein-hyperproducers were reclassified into at least 6 species according to numerical analysis, DNA base composition, and DNA-DNA hybridization. We developed a host-vector system using appropriate strains of these Bacillus brevis as a host, which is excellent for the secretion of heterologous proteins. Utilizing the powerful promoters and signal peptide-coding regions of the cell wall protein gene, various expression-secretion vectors were constructed. The cell wall protein genes of these B. brevis are transcribed from multiple and tandemly arranged promoters. Transcription from P2, one of the major promoters among them, was enhanced at the early stationary phase of growth, when divalent cations in the medium was depleted and the cell wall protein layers started to be shed. Translation of the cell wall protein gene transcripts starts at the two sites located tandemly in the same reading frame. The two forms of secretory precursors, translation products from the two sites, are cleaved at the same position giving rise to the same mature proteins. The nucleotide sequence from the promoter to the translation start site is highly conserved in protein-hyperproducing B. brevis. For the efficient secretion of some heterologous proteins, protein-hypersecreting mutants had to be selected. The engineering of the signal peptide was also often necessary to obtain a good secretion of heterologous proteins.(ABSTRACT TRUNCATED AT 250 WORDS)
Amino Acid Sequence↗