Thin films of the short single DNA strand, GCAT, in which one of the bases has been removed were bombarded with 3 to 15 eV electrons. The yield functions of the H(-), O(-) and OH(-) ions desorbed from these films exhibit a broad peak near 9 eV, which is attributed to dissociative electron attachment to the basic molecules. Whereas removal of any one of the bases considerably decreases N-glycosi...

We have determined the x-ray structure of a DNA fragment containing 7,8-dihydro-8-oxoguanine (G(O)). The structure of the duplex form of d(CCAGOCGCTGG) has been determined to 1.6-A resolution. The results demonstrate that GO forms Watson-Crick base pairs with the opposite C and that G(O) is in the anti conformation. Structural perturbations induced by C.G(O)anti base pairs are subtle. The struc...

To guide the design of alternative genetic systems, we measured melting temperatures of DNA duplexes containing matched and mismatched nucleobase pairs from natural and unnatural structures. The pairs were analyzed in terms of structural features, including nucleobase size, number of hydrogen bonds formed, the presence of uncompensated hydrogen bonding functional groups, the nature of the bond ...

The present studies were undertaken to determine the mechanism by which attachment of the carcinogen N-2-acetylaminofluorene to guanosine residues in nucleic acids distors their structure and function. Oligonucleotides were modified with N-acetoxy-2-acetylaminofluorene, repurified, and their base compositions analyzed. Evidence is presented that acetylaminofluorene residues bound to guanosines ...

Cyclodextrin glycosyltransferase (CGTase) is a member of the a-amylase family, a large group of enzymes that act on a-glycosidic bonds in starch and related compounds. Over twenty different reaction and product specificities have been found in this family. Although three-dimensional structure elucidation and the biochemical characterization of site-directed mutants have yielded a detailed insig...

Structural analysis of sulfated oligosaccharides from -carrageenan of up to ten residues (MW 2 kDa) was successfully carried out by positive mode nano-ESI-FTICR-MS together with MS/MS using sustained off-resonance irradiation-collision induced dissociation (SORI-CID). Glycosidic bond cleavage reactions via the Band Y-types of fragmentation were observed and enabled complete sequencing of the ol...

The maltooligosyl trehalose synthase gene from the hyperthermophilic archaeon Sulfolobus tokodaii strain 7 was cloned and the recombinant peotein was expressed in E. coli. The protein was purified to homogeneity by nickel column chromatography. The archaeal enzyme could catalyze an intramolecular transglycosylation reaction and convert the glycosidic bond at the reducing end of dextrins from α-...

Potassium salt is a nonnegligible inorganic element in biomass, and it has significant impact on the thermal behavior of biomass. To understand mechanism potassium cellulose pyrolysis depth, evolution functional groups char combined with characteristics volatiles from K2CO3 between 150 600 °C was investigated using two-dimensional perturbation correlation infrared spectroscopy (2D-PCIS). It fou...

Phenylethanoid glycosides (PhGs) are widely distributed in traditional Chinese medicines as well as in other medicinal plants, and they were characterized by a phenethyl alcohol (C₆-C₂) moiety attached to a β-glucopyranose/β-allopyranose via a glycosidic bond. The outstanding activity of PhGs in diverse diseases proves their importance in medicinal chemistry research. This review summarizes new...