Biomedical subjects

C Gilon

Publications and source records attributed to C Gilon.

92 records · Page 6Linked to original sources

PubMedDate not supplied

Characterization of a putative pheromone biosynthesis-activating neuropeptide (PBAN) receptor from the pheromone gland of Heliothis peltigera.

The binding of [(3)H]tyrosyl-PBAN28-33NH(2) to pheromone gland membranes of the moth Heliothis peltigera was investigated. The study describes the development of a pheromone biosynthesis-activating neuropeptide (PBAN) radioreceptor assay and demonstrates the presence of a putative PBAN binding site on the pheromone gland. It also describes synthesis of a radioligand and optimization of binding conditions with respect to membrane preparation, number of gland equivalents, kinetics of ligand binding and composition of the binding solution. Binding was found to be optimal when membranes were freshly prepared from frozen glands, incubated at a concentration of one gland equivalent per reaction tube in the presence of 10 mM HCO(3)(-) ions. Equilibrium of ligand binding was obtained after 20 min. Presence of other components such as NaCl, KCl or SH reagents did not have any effect on binding. Binding was found to be saturable, with a K(d) of 5.73 +/- 1.05 x 10(-6) M and a Bmax of 1.85 +/- 0.22 nmol/mg protein. Binding was effectively displaced by unlabeled PBAN1-33NH(2) and PBAN28-33NuEta(2) with a K(i) of 4.3 +/- 1.1 x 10(-6) M and 4.9 +/- 2.6 x 10(-6) M, respectively.

Animals↗

PubMedDate not supplied

Polydepsipeptides. 5. Experimental conformational analysis of poly(L-alanyl-L-lactic acid) and related model compounds.

In this paper we report an experimental conformational analysis of the depsipeptide model compounds acetyl-L-alanine methyl ester, acetyl-L-lactic acid N-methylamide, and acetyl-L-alanyl-L-lactic acid N-methylamide and of the sequential polydepsipeptide poly(L-alanyl-L-lactic acid). The model depsipeptides were examined in dilute organic solutions by infrared and nuclear magnetic resonance spectroscopy. Neither acetyl-L-alanine methyl ester nor acetyl-L-lactic acid N-methylamide assumes an intramolecularly hydrogen-bonded conformation. Acetyl-L-alanyl-L-lactic acid N-methylamide, on the other hand, in dilute chloroform or dilute carbon tetrachloride solutions, strongly favors a conformation with an intramolecular hydrogen bond between the N-H hydrogen atom of its N-methylamide group and the carbonyl oxygen atom of its acetyl group. Comparison of theoretical and experimental circular dichroism suggests that poly(L-alanyl-L-lactic acid) is partially ordered in chloroform solution with approximately 50% of its repeat units in the R10 helix, an ordered conformation found by our previous theoretical analysis to have a low intramolecular conformational energy.

Alanine↗