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J Dubach

Publications and source records attributed to J Dubach.

17 recordsLinked to original sources
PubMed1996

Behavior predicts genes structure in a wild primate group.

The predictability of genetic structure from social structure and differential mating success was tested in wild baboons. Baboon populations are subdivided into cohesive social groups that include multiple adults of both sexes. As in many mammals, males are the dispersing sex. Social structure and behavior successfully predicted molecular genetic measures of relatedness and variance in reproductive success. In the first quantitative test of the priority-of-access model among wild primates, the reproductive priority of dominant males was confirmed by molecular genetic analysis. However, the resultant high short-term variance in reproductive success did not translate into equally high long-term variance because male dominance status was unstable. An important consequence of high but unstable short-term variance is that age cohorts will tend to be paternal sibships and social groups will be genetically substructured by age.

Animals↗
PubMed1991

Effect of the synergistic anion on electron paramagnetic resonance spectra of iron-transferrin anion complexes is consistent with bidentate binding of the anion.

Continuous wave (cw) X-band EPR spectra at approximately 90 K were obtained for iron-transferrin-anion complexes with 18 anions. Each anion had a carboxylate group and at least one other polar moiety. As the second polar group was varied from hydroxyl to carbonyl to amine to carboxylate, the EPR spectra changed from a dominant signal at g' approximately 4.3 with a second smaller peak at g' approximately 9 to a broad signal with intensity between g' approximately 5 and 7. Computer simulation indicated that the changes in the EPR spectra were due to changes in the zero field splitting parameter ratio, E/D, from approximately 1/3 for carbonate anion to approximately 0.04 for malonate anion. Observation of iron-13C coupling in the electron spin echo envelope modulation (ESEEM) for iron transferrin [1-13C]pyruvate indicated that the carboxylate group was bound to the iron. It is proposed that all of the anions behave as bidentate ligands, with coordination to the iron through both the carboxylate and proximal groups, and the carboxyl group serves as a bridge between the iron and a positively charged group on the protein.

Anions↗
PubMed1990

Electron spin echo envelope modulation evidence for carbonate binding to iron(III) and copper(II) transferrin and lactoferrin.

Iron binding to transferrin and lactoferrin requires a synergistic anion, which is carbonate in vivo. The anion is thought to play a key role in iron binding and release. To understand better the iron-carbonate interaction, experiments were performed with iron(III) and copper(II) complexes of human milk lactoferrin and serum transferrin with carbon-13-labeled carbonate. Modulation frequencies were present in the Fourier transforms of two-pulse and three-pulse electron spin echo envelope modulation data for the Fe(III) and Cu(II) complexes, consistent with binding of carbonate to both metals. The metal-13C interaction was similar for the lactoferrin and transferrin complexes. Spin coupling to the nitrogen of a coordinated histidine imidazole was observed for both metals. Both the metal-nitrogen and the metal-carbon spin coupling constants were about a factor of 5 smaller for the iron complexes than for the copper complexes, which indicated substantial similarity in the metal-carbonate and metal-imidazole binding for the two metals.

Carbonates↗
PubMed1989

Comparison of the electron spin echo envelope modulation (ESEEM) for human lactoferrin and transferrin complexes of copper(II) and vanadyl ion.

Copper(II) and vanadyl ions were bound to human milk lactoferrin or serum transferrin with carbonate or oxalate as the synergistic anion. Electron spin echo envelope modulation (ESEEM) due to nitrogen of a coordinated histidine imidazole was observed for both the copper and vanadyl complexes. For both metals, the modulation frequencies in the Fourier transforms of the data were similar for the two proteins and were weakly dependent on anion. When data in D2O/glycerol-d3 were compared with data in H2O/glycerol, the deep deuterium modulation indicated multiple exchangeable protons in the vicinity of the metals with at most one proton within about 2.9 A of the metal. The distribution of exchangeable protons around the metals as probed by ESEEM was the same, within experimental uncertainty, for the copper or vanadyl complexes with either carbonate or oxalate as the anion. When 13C-labeled oxalate was used as the synergistic anion, 13C-ESEEM was observed for both the copper and vanadyl complexes of lactoferrin and transferrin. The deeper 13C modulation for copper and vanadyl transferrin [13C]oxalate than for vanadyl transferrin [13C]carbonate suggests that both ends of the oxalate are bound to the metal in the transferrin and lactoferrin complexes.

Copper↗