The mechanism of nucleohistone degradation in calf thymus chromatin during autolysis of the latter involves a release of lysine-rich histone fractions, followed by degradation of the thus-exposed DNA portions; the latter portions are richest in adenine-thymine sequences. After this degradation process, residual nucleohistone fragments of low molecular weight (105) remain. Their chemical composi...

In the presence of alkali and LAuCl one or two —N H — groups of a purine or pyrimidine base can be transformed into -N (AuL)groups giving stable and soluble compounds containing one or two two-coordinated gold(I) nuclei; mononuclear L A u-Q ' or binuclear LA u-Q -A uL with a monodentate Q " or an exobidentate O '" ligand, resp. (Q 'H = adenine, guanine, theobromine, theophylline, azaguanine or ...

The base composition of deoxyribonucleic acid (DNA) prepared from four Betabacterium strains and four Streptobacterium strains was determined. Per cent GC values (guanine + cytosine/total bases) of the DNA were evaluated from the "melting-temperatures" (Tm) of the nucleic acids. For the Betabacterium strains, these values ranged from 44 to 51.5% GC, and those for the Streptobacterium strains ra...

We have used the CNDO/2-CI method to calculate the isopotential maps for the fundamental state and the direction of the polarizations corresponding to several singlet transitions in the mole­ cules of guanine, cytosine and tautomeric forms. We have also calculated the times for proton tunneling and equilibrium constants between both conformers corresponding to the fundamental and some excited s...

A novel method for the deprotection of oligodeoxyribonucleotides has been developed. Gaseous amines such as ammonia or methylamine were employed under pressure to achieve mild and rapid deprotection conditions. For example, oligodeoxyribonucleotides having a (tert-butyl)phenoxyacetyl group for the protection of the exocyclic amino function of cytosine, adenine and guanine were released from con...

• A DNA molecule consists of two strands, commonly referred to as top and bottom; positive and negative; or normal and reverse. The contents of one strand form a reverse complement of the other strand. The ”complement” part: A(denine) is always paired with Thymine, while Cytosine is always paired with Guanine. The ”reverse” part: the strand are read in opposite directions: the 5’ end of one str...

pGC1, a self-transmissible lac plasmid that originated in Yersinia enterocolitica 842, is described. This plasmid is freely transmissible between strains of Y. enterocolitica and from such strains to strains of Escherichia coli. The plasmid can also be transferref among G. coli strains and back to Y. enterocolitica, although at a greatly reduced frequency. pGC1 has a molecular weight of about 3...

An improved synthesis of glycol nucleic acids is reported using new phosphoramidite building blocks in which the exocyclic amino groups of adenine and guanine are protected as N-dimethylformamidines, whereas the amino group of cytosine is protected via an acetamide. Besides a more rapid synthesis with higher yields, these phosphoramidites allow the use of a quicker deprotection procedure in the...

RP1, a group of genes specifying resistance to carbenicillin, neomycin, kanamycin, and tetracycline and originating in a strain of Pseudomonas aeruginosa, was freely transmissible between strains of P. aeruginosa, Escherichia coli, and Proteus mirabilis. Acquisition of the multiple drug resistance specified by RP1 by these strains was accompanied by acquisition of an extrachromosomal satellite ...

Quantum chemical high level ab initio coupled-cluster and multiconfigurational perturbation methods have been used to compute vertical and adiabatic ionization potentials of the five canonical DNA and RNA nucleobases: uracil, thymine, cytosine, adenine, and guanine. Several states of their cations have been also calculated. The present results represent a systematic compendium of these magnitud...