Takashi Shiraki

Man-designed bleomycins: Significance of the binding sites as enzyme models and of the stereochemistry of the linker moiety

Abstract Comparison of the DNA cleavage activity of man-designed bleomycins demonstrates that belomycins are small enzymes comprised of a catalytic site and a binding site. The linker moiety is shown to be significant for DNA binding, and inversion of its stereochemistry results in a dramatic decrease in the DNA-cleaving efficiency. One of the man-designed BLMs shows excellent cytotoxicity against L1210.

C-1′ hydrogen abstraction of deoxyribose in DNA strand scission by dynemicin A

Dynemicin A, which is a hybrid antitumor antibiotic containing anthraquinone and enediyne cores, abstracts the C-1 hydrogen of DNA deoxyribose and then the damaged DNA leads to strand breaks with the formation of 5- and 3-phosphate termini. The lesions of C-4 hydrogen also occur at 3 side of G.C base pairs (i. e., 5-CT and 5-GA), leading to 5-phosphate and 3-phosphoglycolate termini or 4-hydroxylated abasic sites. The C-1 hydrogen abstraction by dynemicin A is distinct from the preferential C-5 hydrogen abstraction of calicheamicin and neocarzinostatin.

Augmenting a Submodular and Posi-modular Set Function by a Multigraph

AbstractGiven a finite set V and a set function n

Biological Activity of Water-Soluble Fullerenes. Structural Dependence of DNA Cleavage, Cytotoxicity, and Enzyme Inhibitory Activities Including HIV-Protease Inhibition

f:2^V mapsto Z

DNA intercalation and cleavage of an antitumor antibiotic dynemicin that contains anthracycline and enediyne cores.

n, we consider the problem of constructing an undirected multigraph G = (V,E) such that the cut function n

Reductive and nucleophilic activation products of dynemicin A with methyl thioglycolate. A rational mechanism for DNA cleavage of the thiol-activated dynemicin A

C_G :2^V mapsto Z{text{ of }}G{text{ and }}f