ATP production system with a methylotrophic yeast, Candida boidinii, was investigated. Adenylate kinase activity for converting AMP to ADP was revealed to be the rate-limiting step in the ATP production system with C. boidinii No. 2201. Using the recently developed transformation system for C. boidinii, ADK activity was enhanced about 5, 000-10, 000-fold in C. boidinii cells. The obtained 3-copy multiple integrant strain CT100 cells, were shown to have higher ATP productivity than the control strain, not only for ATP productivity per cells but for productivity of high catalytic cells. Thus, the ATP productivity was improved by the introduction and expression of heterologous adenylate kinase gene in C. boidinii.
DNA recognition rules for transcription factors of class C4 are discussed in the light of three dimensional structures determined by crystallography or NMR. The rules have two parts; the chemical rules which list possible amino acid side-chains and DNA bases partners, and the Stereochemical rules which describe how the positions of the residues and bases which make contact are determined by the orientation and packing of the α-helix in the major groove of DNA.
The DNA recognition rules for transcription factors of the C4 class described in the preceeding paper are further examined. By designing a computer program we show that the rules are specific enough to predict binding sites in the regulatory sequences of DNA.
The effect of guanidino compounds other than creatin(in)e on mutagen formation was tested after heating with amino acid and glucose in a solution at 128°C for 2h. The mutagenicity of a heated mixture of creatine, glycine and glucose to Salmonellatyphimurium TA98 with S9 mix was 630 per mg of heated material. When L-arginine was mixed with glycine plus glucose, 39 revertants of TA98 were induced per mg of heated material. Other guanidino compounds such as NG-methyl-L-arginine, 1-methylguanidine, aminoguanidine and guanidine also yielded mutagens, inducing 6.0-64 revertants per mg of heated material. When guanidino compounds were heated with L-phenylalanine and glucose, mixtures also yielded mutagenicity. The mutagenicity of a heated mixture of creatine, L-phenylalanine and glucose to TA98 with S9 mix was 160 per mg of heated material. L-Arginine, NG-methyl-L-arginine, aminoguanidine and guanidine gave 1.9-21 revertants per mg of heated material. With the addition of 1-methylguanidine, a very potent mutagenicity of 200 per mg of heated material was observed.