It is known that a general polyhedral scene of complexity n has at most O(n6) combinatorially different orthographic views and at most O(n9) combinatorially different perspective views, and that these bounds are tight in the worst case. In this paper we show that, for the special case of scenes consisting of a collection of n translates of a cube, these bounds improve to O(n4+ε) and O(n6+ε), fo...

The asymmetric unit of the title co-crystal, C12H9N5O·C7H6O3, contains one mol-ecule of N6-benzoyl-adenine (BA) and one mol-ecule of 4-hy-droxy-benzoic acid (HBA). The N6-benzoyl-adenine (BA) has an N(7)-H tautomeric form with nonprotonated N-1 and N-3 atoms. This tautomeric form is stabilized by a typical intra-molecular N-H⋯O hydrogen bond between the carbonyl (C=O) group and the N(7)-H hydro...

Although adenosine is known to activate K+ conduction in atrial tissue, there is still debate as to the involvement of cAMP-dependent mechanisms. In isolated adult guinea pig atrial myocytes, we demonstrate that the highly A1-selective adenosine receptor agonist 2-chloro-N6-cyclopentyladenosine reduced basal cAMP levels by 30-40% in the absence and presence of the nonxanthine phosphodiesterase ...

Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) from the sleeping sickness parasite Trypanosoma brucei is a rational target for anti-trypanosomatid drug design because glycolysis provides virtually all of the energy for the bloodstream form of this parasite. Glycolysis is also an important source of energy for other pathogenic parasites including Trypanosoma cruzi and Leishmania mexicana. The ...

DNA N6-methyladenine modification plays an important role in regulating a variety of biological functions in bacteria. However, the mechanism of sequence-specific recognition in N6-methyladenine modification remains elusive. M1.HpyAVI, a DNA N6-adenine methyltransferase from Helicobacter pylori, shows more promiscuous substrate specificity than other enzymes. Here, we present the crystal struct...

A single high-affinity binding site for adenine and related compounds was identified in the lima bean lectin (LBL) component III tetramer. This site is identical with the high affinity site for 2,6-toludinyl-naphthalenesulfonate described previously (Roberts, D. D., and Goldstein, I. J. (1982) J. Biol. Chem. 257, 11274-11277). [14C]Adenine was bound with high affinity (Kd = 1.2 +/- 0.1 X 10(-5)...

N6-Methyladenosine is a ubiquitous modification identified in the mRNA of numerous eukaryotes, where it is present within both coding and noncoding regions. However, this base modification does not alter the coding capacity, and its biological significance remains unclear. We show that Arabidopsis thaliana mRNA contains N6-methyladenosine at levels similar to those previously reported for anima...

Lactose permease of Escherichia coli is a polytopic membrane transport protein containing 12 membrane-spanning segments. When the amino (N6)- and carboxy (C6)-terminal halves are expressed as separate gene fragments, association of the first half (N6) of the permease with the second half (C6) is necessary for stable insertion of C6 [Bibi, E., & Kaback, H. R. (1990) Proc. Natl. Acad. Sci. U.S.A....

1. Erabutoxins a, b and c, neurotoxic proteins of a sea snake Laticauda semifasciata, were guanidinated with O-methylisourea. The amino groups of all the lysine residues and those at the N-termini of the toxins were modified. The lethal activity of the toxins decreased to 50% (erabutoxins a and b) or 17% (erabutoxin c) of the original value on the modification. The c.d. (circular dichroism) max...

2-Arylethynyl derivatives of (N)-methanocarba adenosine 5'-uronamides are selective A3AR (adenosine receptor) agonists. Here we substitute a 1,2,3-triazol-1-yl linker in place of the rigid, linear ethynyl group to eliminate its potential metabolic liability. Docking of nucleosides containing possible short linker moieties at the adenine C2 position using a hybrid molecular model of the A3AR (ba...