Cohort, Policy, and Process: The Implications for Migrant Fertility in West Germany.

Although a growing literature explores the relationship between migration and fertility, far less scholarship has examined how migrant childbearing varies over time, including across migrant cohorts. I extend previous research by exploring migrant-cohort differences in fertility and the role of changing composition by education and type of family migration. Using 1984-2016 German Socio-Economic Panel data, I investigate the transition into first, second, and third birth among foreign-born women in West Germany.

Childhood Origins, Migration, and First Modern Contraceptive Use in Turkey.

This paper integrates contraception into the extant migrant-fertility framework using the case of internal migration within Turkey. Drawing from the 2013 Turkish Demographic and Health Survey data, we show that migration is positively associated with age of first modern contraceptive use. As women's migration is quickly followed by family formation, women also take up modern contraception after first childbirth, likely due to new encounters with medical professionals, differing contraceptive access and other social exposures.

Parental Separation and School Performance Among Children of Immigrant Mothers in Sweden.

Immigration and family change are two demographic processes that have changed the face of European societies and are associated with inequalities in child outcomes. Yet there is little research outside the USA on whether the effects of family dynamics on children's life chances vary by immigrant background. We asked whether the effect of parental separation on educational achievement varies between immigrant backgrounds (ancestries) in Sweden.

pH dependence of cyanide and imidazole binding to the heme domains of Sinorhizobium meliloti and Bradyrhizobium japonicum FixL.

Equilibrium and kinetic properties of cyanide and imidazole binding to the heme domains of Sinorhizobium meliloti and Bradyrhizobium japonicum FixL (SmFixLH and BjFixLH) have been investigated between pH5 and 11. KD determinations were made at integral pH values, with the strongest binding at pH9 for both ligands. KD for the cyanide complexes of BjFixLH and SmFixLH is 0.

Binding of Yeast Cytochrome c to Forty-Four Charge-Reversal Mutants of Yeast Cytochrome c Peroxidase: Isothermal Titration Calorimetry.

Previously, we constructed, expressed, and purified 46 charge-reversal mutants of yeast cytochrome c peroxidase (CcP) and determined their electronic absorption spectra, their reaction with H2O2, and their steady-state catalytic properties [ Pearl , N. M. et al.

Binding of imidazole, 1-methylimidazole and 4-nitroimidazole to yeast cytochrome c peroxidase (CcP) and the distal histidine mutant, CcP(H52L).

Imidazole, 1-methylimidazole and 4-nitroimidazole bind to yeast cytochrome c peroxidase (yCcP) with apparent equilibrium dissociation constants (KD(app)) of 3.3±0.4, 0.

Apolar distal pocket mutants of yeast cytochrome c peroxidase: Binding of imidazole, 1-methylimidazole and 4-nitroimidazole to the triAla, triVal, and triLeu variants.

Imidazole binding to three apolar distal heme pocket mutants of yeast cytochrome c peroxidase (CcP) has been investigated between pH4 and 8. The three CcP variants have Arg-48, Trp-51, and His-52 mutated to either all alanine, CcP(triAla), all valine, CcP(triVal), or all leucine residues, CcP(triLeu). The imidazole binding curves for all three mutants are biphasic indicating that each of the mutants exists in at least two conformational states with different affinities for imidazole.

Kinetic and equilibrium studies of acrylonitrile binding to cytochrome c peroxidase and oxidation of acrylonitrile by cytochrome c peroxidase compound I.

Ferric heme proteins bind weakly basic ligands and the binding affinity is often pH dependent due to protonation of the ligand as well as the protein. In an effort to find a small, neutral ligand without significant acid/base properties to probe ligand binding reactions in ferric heme proteins we were led to consider the organonitriles. Although organonitriles are known to bind to transition metals, we have been unable to find any prior studies of nitrile binding to heme proteins.

Peroxygenase activity of cytochrome c peroxidase and three apolar distal heme pocket mutants: hydroxylation of 1-methoxynaphthalene.

Background: The cytochrome P450s are monooxygenases that insert oxygen functionalities into a wide variety of organic substrates with high selectivity. There is interest in developing efficient catalysts based on the "peroxide shunt" pathway in the cytochrome P450s, which uses H2O2 in place of O2/NADPH as the oxygenation agent. We report on our initial studies using cytochrome c peroxidase (CcP) as a platform to develop specific "peroxygenation" catalysts.

Apolar distal pocket mutants of yeast cytochrome c peroxidase: hydrogen peroxide reactivity and cyanide binding of the TriAla, TriVal, and TriLeu variants.

Three yeast cytochrome c peroxidase (CcP) variants with apolar distal heme pockets have been constructed. The CcP variants have Arg48, Trp51, and His52 mutated to either all alanines, CcP(triAla), all valines, CcP(triVal), or all leucines, CcP(triLeu). The triple mutants have detectable enzymatic activity at pH 6 but the activity is less than 0.

Effect of alternative distal residues on the reactivity of cytochrome c peroxidase: properties of CcP mutants H52D, H52E, H52N, and H52Q.

To test the effect of alternative bases at the distal histidine position, four CcP variants have been constructed that substitute the two basic residues, aspartate and glutamate, and their amides, asparagine and glutamine, for histidine-52, i.e., CcP(H52D), CcP(H52E), CcP(H52N), and CcP(H52Q).

Reduction potential of yeast cytochrome c peroxidase and three distal histidine mutants: dependence on pH.

The pH dependence of the Fe(III) reduction potential, E(0)', for yeast cytochrome c peroxidase (yCcP) and three distal pocket mutants, CcP(H52L), CcP(H52Q), and CcP(R48L/W51L/H52L), has been determined between pH 4 and 8. E(0)' values at pH 7.0 for the yCcP, CcP(H52L), CcP(H52Q), and CcP(R48L/W51L/H52L) are -189, -170, -224, and -146mV, respectively.

Relocation of the distal histidine in cytochrome c peroxidase: properties of CcP(W51H), CcP(W51H/H52W), and CcP(W51H/H52L).

Many heme proteins have distal histidine residues that play important roles in determining heme protein reactivity. These distal histidines are in significantly different orientations,and distances from the heme iron in different heme proteins and the position of the distal histidine relative to the heme iron can influence reactivity at the heme center. To explore the effect of distal histidine position on the properties of cytochrome c peroxidase (CcP), three CcP mutants in which tryptophan 51 was replaced with a histidine residue were constructed.

pH dependence of cyanide binding to the ferric heme domain of the direct oxygen sensor from Escherichia coli and the effect of alkaline denaturation.

The spectrum of the ferric heme domain of the direct oxygen sensor protein from Escherichia coli ( EcDosH) has been measured between pH 3.0 and 12.6.

Effect of single-site charge-reversal mutations on the catalytic properties of yeast cytochrome c peroxidase: evidence for a single, catalytically active, cytochrome c binding domain.

Forty-six charge-reversal mutants of yeast cytochrome c peroxidase (CcP) have been constructed in order to determine the effect of localized charge on the catalytic properties of the enzyme. The mutants include the conversion of all 20 glutamate residues and 24 of the 25 aspartate residues in CcP, one at a time, to lysine residues. In addition, two positive-to-negative charge-reversal mutants, R31E and K149D, are included in the study.

Mass instability in isolated recombinant FixL heme domains of Bradyrhizobium japonicum.

Several recombinant Bradyrhizobium japonicum FixL heme domains (BjFixLH) have been characterized and their temporal mass stabilities assessed by MALDI-TOF mass spectrometry. The intact heme domains all bound heme and gave normal UV-visible spectra, indicating that they were correctly assembled. Proteins produced at Washington State University included a parent 131-amino acid "full-length heme domain" (FLHD) of primary sequence T140-Q270 (BjFixLH140-270), a histidine-tagged analogue containing an N-terminal extension, and five different terminus-truncated variants.

Effect of single-site charge-reversal mutations on the catalytic properties of yeast cytochrome c peroxidase: mutations near the high-affinity cytochrome c binding site.

Fifteen single-site charge-reversal mutations of yeast cytochrome c peroxidase (CcP) have been constructed to determine the effect of localized charge on the catalytic properties of the enzyme. The mutations are located on the front face of CcP, near the cytochrome c binding site identified in the crystallographic structure of the yeast cytochrome c-CcP complex [Pelletier, H., and Kraut, J.

Effect of active site and surface mutations on the reduction potential of yeast cytochrome c peroxidase and spectroscopic properties of the oxidized and reduced enzyme.

The reduction potentials of 22 yeast cytochrome c peroxidase (CcP) mutants were determined at pH 7.0 in order to determine the effect of both heme pocket and surface mutations on the Fe(III)/Fe(II) redox couple of CcP, as well as to determine the range in redox potentials that could be obtained through point mutations in the enzyme. Spectroscopic properties of the Fe(III) and Fe(II) forms of the mutant enzymes are also reported.

Characterization of four covalently-linked yeast cytochrome c/cytochrome c peroxidase complexes: Evidence for electrostatic interaction between bound cytochrome c molecules.

Four covalent complexes between recombinant yeast cytochrome c and cytochrome c peroxidase (rCcP) were synthesized via disulfide bond formation using specifically designed protein mutants (Papa, H. S., and Poulos, T.

Characterization of a covalently linked yeast cytochrome c-cytochrome c peroxidase complex: evidence for a single, catalytically active cytochrome c binding site on cytochrome c peroxidase.

A covalent complex between recombinant yeast iso-1-cytochrome c and recombinant yeast cytochrome c peroxidase (rCcP), in which the crystallographically defined cytochrome c binding site [Pelletier, H., and Kraut, J. (1992) Science 258, 1748-1755] is blocked, was synthesized via disulfide bond formation using specifically engineered cysteine residues in both yeast iso-1-cytochrome c and yeast cytochrome c peroxidase [Papa, H.

pH Dependence of heme iron coordination, hydrogen peroxide reactivity, and cyanide binding in cytochrome c peroxidase(H52K).

Replacement of the distal histidine, His-52, in cytochrome c peroxidase (CcP) with a lysine residue produces a mutant cytochrome c peroxidase, CcP(H52K), with spectral and kinetic properties significantly altered compared to those of the wild-type enzyme. Three spectroscopically distinct forms of the enzyme are observed between pH 4.0 and 8.

Azide binding to yeast cytochrome c peroxidase and horse metmyoglobin: comparative thermodynamic investigation using isothermal titration calorimetry.

Yeast cytochrome c peroxidase (CcP) and horse metmyoglobin (Mb) bind HN3 with similar affinities at 25 degrees C. The pH-independent equilibrium association constants for formation of the CcP.HN3 and Mb.

Temperature, pH, and solvent isotope dependent properties of the active sites of resting-state and cyanide-ligated recombinant cytochrome c peroxidase (H52L) revealed by proton hyperfine resonance spectra.

Comparative proton NMR studies have been carried out on high-spin and low-spin forms of recombinant native cytochrome c peroxidase (rCcP) and its His52 --> Leu variant. Proton NMR spectra of rCcP(H52L) (high spin) and rCcP(H52L)CN (low spin) reveal the presence of multiple enzyme forms in solution, whereas only single enzyme forms are found in spectra of wild-type and recombinant wild-type CcP and CcPCN near neutral pH. The spectroscopic behaviors of these forms have been studied in detail when pH, temperature, and solvent isotope composition were varied.

Cyanide binding to cytochrome c peroxidase (H52L).

Cyanide binding to a cytochrome c peroxidase (CcP) variant in which the distal histidine has been replaced by a leucine residue, CcP(H52L), has been investigated as a function of pH using spectroscopic, equilibrium, and kinetic methods. Between pH 4 and 8, the apparent equilibrium dissociation constant for the CcP(H52L)/cyanide complex varies by a factor of 60, from 135 microM at pH 4.7 to 2.

Yeast cytochrome c peroxidase: mechanistic studies via protein engineering.

Cytochrome c peroxidase (CcP) is a yeast mitochondrial enzyme that catalyzes the reduction of hydrogen peroxide to water by ferrocytochrome c. It was the first heme enzyme to have its crystallographic structure determined and, as a consequence, has played a pivotal role in developing ideas about structural control of heme protein reactivity. Genetic engineering of the active site of CcP, along with structural, spectroscopic, and kinetic characterization of the mutant proteins has provided considerable insight into the mechanism of hydrogen peroxide activation, oxygen-oxygen bond cleavage, and formation of the higher-oxidation state intermediates in heme enzymes.