We present a next-to-leading order calculation for the virtual photoproduction of one and two jets in ep collisions. Soft and collinear singularities are extracted using the phase space slicing method. The collinear photon initial state singularity depends logarithmically on the mass of the virtual photon and is absorbed into the virtual photon structure function. An MS factorization scheme is defined similarly to the real photon case. Numerical results are presented for HERA conditions using the Snowmass jet definition for inclusive single jet and dijet cross sections. We study the dependence of these cross sections on the transverse energies and rapidities of the jets. Finally, we compare the ratio of the experimentally defined resolved and direct cross sections with recent ZEUS data as a function of the photon virtuality P 2 .

The three ribonucleic acids (RNAs) from Escherichia coli ribosomes were isolated and then labeled at their 3' ends by oxidation with periodate followed by reaction with thiosemicarbazides of fluorescein or eosin. Ribosomal subunits reconstituted with the labeled RNAs were active for polyphenylalanine synthesis. The distances between the 3' ends of the RNAs in 70S ribosomes were estimated by nonradiative energy transfer from fluorescein to eosin. The percentage of energy transfer was calculated from the decrease in fluorescence lifetime of fluorescein in the quenched sample compared to the unquenched sample. Fluorescence lifetime was measured in real time by using a mode-locked laser for excitation and a high-speed electrostatic photomultiplier tube for detection of fluorescence. The distances between fluorophores attached to the 3' ends of 16S RNA and 5S RNA or 23S RNA were estimated to be about 55 and 71 A, respectively. The corresponding distance between the 5S RNA and 23S RNA was too large to be measured reliably with the available probes but was estimated to be greater than 65 A. Comparison of the quantum yields of the labeled RNAs free in solution and reconstituted into ribosomal subunits suggests that the 3' end of 16S RNA does not interact appreciably with other ribosomal components and may be in a relatively exposed position, whereas the 3' ends of the 5S RNA and 23S RNA may be buried in the 70S ribosomal subunit.

Large subunits of E. coli ribosomes, specifically 23S rRNA, have the capacity to mediate refolding of denatured rhodanese. Refolding activity is related to the state or conformation of ribosomes that is promoted by EF-G. Activation by either mechanism is strongly inhibited by the EF-G.GDP.fusidic acid complex.

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Highly purified preparations of the heme-controlled eIF-2 alpha (eukaryotic peptide initiation factor 2 alpha subunit) kinase of rabbit reticulocytes contain an abundant 90-kilodalton (kDa) peptide that is immunologically cross-reactive with spectrin and that modulates the activity of the enzyme [Kudlicki, W., Fullilove, S., Read, R., Kramer, G., & Hardesty, B. (1987) J. Biol. Chem. 262, 9695-9701]. The amino-terminal sequence of the 90-kDa protein has a high degree of similarity with the known amino-terminal sequences of the Drosophila 83-kDa heat shock protein (20 out of 22 residues) and with other related heat shock proteins. The amino acid sequence of a tryptic phosphopeptide isolated by high-performance liquid chromatography from the eIF-2 alpha kinase associated 90-kDa protein after phosphorylation by casein kinase II is shown to be identical with a 14 amino acid segment of the known sequence of the Drosophila 83-kDa heat shock protein. Results of hydrodynamic studies indicate a highly elongated structure for the reticulocyte protein, characteristic of a structural protein. Additional structural similarities between the eukaryotic heat shock proteins, the reticulocyte eIF-2 alpha kinase associated 90-kDa peptide, and spectrin are discussed.