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All eukaryotic sialyltransferases have in common the presence in their catalytic domain of several conserved peptide regions (sialylmotifs L, S, and VS). Functional analysis of sialylmotifs L and S previously demonstrated their involvement in the binding of donor and acceptor substrates. The region comprised between the sialylmotifs S and VS contains a(More)
  • D M Soumpasis
  • 1984
A theoretical framework is constructed to treat the effects of salt ions on polyionic structural transitions in the absence of specific ion binding. As an application, the salt concentration-dependent part of the free energy difference governing the B----ZI transition of [d(C-G) . d(C-G)]6 in 1:1 electrolytes is calculated; quantitative agreement with the(More)
We have studied the B-Z transition of poly[d(G-C)] in the presence of alkali metal, tetramethylammonium and tetraethylammonium chlorides at room temperature. The measured critical salt concentrations increase in the order Na, K, Rb, TMA, Cs and are in good agreement with the theoretical values predicted from a statistical-mechanical treatment of the(More)
Curved DNA structures can be either intrinsic or induced through interaction with proteins. Large DNA molecules can adopt complex curved shapes in space. Many curved DNA structures (e.g., Cro-operator, Cap-operator, nucleosomal DNA, etc.) are believed to have important biological functions. To model curved DNA molecules is a challenging task. In this work,(More)
Human erythrocytes were incubated in isotonic solutions of different monovalent cations. The apparent size of the red cells measured on scanning electron microscopic pictures decreases in the order Li+>Na+=K+>Rb+. These differences in size are abolished after pretreatment with trypsin, which removes a large part of the charges associated with membrane(More)
We examined more than 700 DNA sequences (full length chromosomes and plasmids) for stretches of purines (R) or pyrimidines (Y) and alternating YR stretches; such regions will likely adopt structures which are different from the canonical B-form. Since one turn of the DNA helix is roughly 10 bp, we measured the fraction of each genome which contains purine(More)
Our proposed description for DNA base/base-pair structures (1), though rigorous, does not satisfy some of the requirements as established at the Cambridge Workshop (2). Here, we propose a revised description for base/base-unit structures of nucleic acids. This new description is as rigorous and satisfies all the requirements (2). Following the original(More)
We propose new, rigorous definitions for (i) basepair fixed coordinate systems and (ii) the twist, tilt, and roll angles (called tau, t, rho) describing the relative orientation of adjacent basepairs and bases in a pair, in arbitrary DNA structures obtained from x-ray diffraction, 2D NMR, or energy calculations. In contrast to the corresponding angular(More)