Revised UV extinction coefficients for nucleoside-5'-monophosphates and unpaired DNA and RNA.

Ultraviolet absorption provides the nearly universal basis for determining concentrations of nucleic acids. Values for the UV extinction coefficients of DNA and RNA rely on the mononucleotide values determined 30-50 years ago. We show that nearly all of the previously published extinction coefficients for the nucleoside-5'-monophosphates are too large, and in error by as much as 7%.

Accurate nucleic acid concentrations by nuclear magnetic resonance.

Determination of the concentration of biochemical samples often yields values with uncertainties of 10-20% or more. This paper details a protocol for use with 500- to 600-MHz NMR spectrometers to measure approximately 1mM concentrations within +/-1-3% accuracy. With suitable precautions, all compounds have equal NMR "absorption coefficients" for protons.

Structure of SL4 RNA from the HIV-1 packaging signal.

The NMR-based structure is described for an RNA model of stem-loop 4 (SL4) from the HIV-1 major packaging domain. The GAGA tetraloop adopts a conformation similar to the classic GNRA form, although there are differences in the details. The type II tandem G.

Investigations of the Copper Bromide-2,2'-Dipyridyl System: Hydrothermal Synthesis and Structural Characterization of Molecular Cu(3)Br(4)(C(10)H(8)N(2))(2), One-Dimensional CuBr(2)(C(10)H(8)N(2)), and Two-Dimensional [Cu(2)(OH)(2)(C(10)H(8)N(2))(2)][Cu(4)Br(6)].

The hydrothermal reactions of CuBr(2), CuBr, and 2,2'-dipyridyl have resulted in the synthesis of three new compounds. Cu(3)Br(4)(C(10)H(8)N(2))(2) (1) is a molecular phase; CuBr(2)(C(10)H(8)N(2)) (2) is a one-dimensional chain structure; and [Cu(2)(OH)(2)(C(10)H(8)N(2))(2)][Cu(4)Br(6)] (3) crystallizes in a two-dimensional sheet structure. All three compounds were characterized by single-crystal X-ray diffraction.