Alkylating agents react with various nitrogen and oxygen atoms in DNA and many of the products are substrates for repair processes. Oxygen atom derivatives such as O6-methylguanine (O6-meG) O4-methylthymine and methylphosphotriesters (MP) have been shown to undergo repair by methyl group removal. The proteins involved in the latter reaction can be considered to be methyltransferases (MT) becaus...

The product of the dcm gene is the only DNA cytosine-C5 methyltransferase of Escherichia coli K-12; it catalyses transfer of a methyl group from S-adenosyl methionine (SAM) to the C-5 position of the inner cytosine residue of the cognate sequence CCA/TGG. Sequence-specific, covalent crosslinking of the enzyme to synthetic oligonucleotides containing 5-fluoro-2'-deoxycytidine is demonstrated. Th...

Rishirilide B was isolated from Streptomyces rishiriensis and Streptomyces bottropensis on the basis of its inhibitory activity towards alpha-2-macroglobulin. The biosynthesis of rishirilide B was investigated by feeding experiments with different 13C labelled precursors using the heterologous host Streptomyces albus J1074::cos4 containing a cosmid encoding of the gene cluster responsible for r...

Electron transfer to rat liver microsomal cytochrome P-450 of 14 alpha-methyl group demethylation of 24,25-dihydrolanosterol (C30-sterol) has been studied with a new radio-high-performance liquid chromatography assay. The monooxygenase is dependent upon NADPH plus oxygen, insensitive to CN-, and sensitive to CO. Microsomal oxidation is also sensitive to trypsin digestion, and reactivation is de...

This Article describes an enantioselective synthesis of cephalostatin 1. Key steps of this synthesis are a unique methyl group selective allylic oxidation, directed C-H hydroxylation of a sterol at C12, Au(I)-catalyzed 5-endo-dig cyclization, and a kinetic spiroketalization.

In the title mol-ecule, C(11)H(14)BrNO, there is twist between the mean plane of the amide group and the benzene ring [C(=O)-N-C C torsion angle = -31.2 (5)°]. In the crystal, inter-molecular N-H⋯O and weak C-H⋯O hydrogen bonds link mol-ecules into chains along [100]. The methyl group H atoms are disordered over two sets of sites with equal occupancy.

An efficient stereoselective synthesis of furanoverrillin (5), a highly functionalized core of verrillin (1), is reported. The synthetic strategy is based on constructing bicyclic lactone 17 prior to the 10-membered ring macrocyclization. The effect of the C4 methyl group on the furan reactivity is also discussed.

In the title quinazolin-4-one derivative, C(23)H(18)N(2)O(3), both the benzoate [dihedral angle = 79.99 (6)°] and the 2-tolyl [89.02 (7)°] groups are close to orthogonal to the central fused ring system. Both aryl groups are orientated towards the quinazolin-4-one-bound methyl group. In the crystal, mol-ecules are connected into a three-dimensional architecture by C-H⋯O, C-H⋯N and C-H⋯π inter-a...

The deficiency of folic acid in the rat produced a reduction in the utilization of either the a-carbon of glycine or the P-carbon of serine for the synthesis of both moieties of choline. On the other hand, the deficiency in vitamin Blz reduced the incorporation of only the a-carbon of glycine; the utilization of the P-carbon of serine was not affected (1). From these data we concluded that vita...