Refining details of the structural and electronic properties of the CuB site in pMMO enzyme through sequential molecular dynamics/CPKS-EPR calculations.

This work investigated the structural and electronic properties of the copper mononuclear site of the PmoB part of the pMMO enzyme at the molecular level. We propose that the CuB catalytic site in the soluble portion of pMMO at room temperature and under physiological conditions is a mononuclear copper complex in a distorted octahedral arrangement with the residues His33, His137, and His139 on the equatorial base and two water molecules on the axial axis. Our view was based on the molecular dynamics results and DFT calculations of the electronic paramagnetic resonance parameters and comparisons with experimental EPR data. This new proposed model for the CuB site brings additional support concerning the recent experimental evidence, which pointed out that a saturated coordination sphere of the copper ion in the CuB center is an essential factor that makes it less efficient than the CuC site in the methane oxidation. Therefore, according to the CuB site model proposed here, an additional step involving a displacement of at least one water molecule of the copper coordination sphere by the O2 molecule prior to its activation must be necessary. This scenario is less likely to occur in the CuC center once this one is buried in the alpha-helices, which are part of the pMMO structure bound to the membrane wall, and consequently located in a less solvent-exposed region. In addition, we also present a simple and efficient sequential S-MD/CPKS protocol to compute EPR parameters that can, in principle, be expanded for the study of other copper-containing proteins.

Ethnic inequality in Guatemalan women's use of modern reproductive health care.

CONTEXT: Guatemala has some of the poorest reproductive health indices and largest disparities in health in Latin America, particularly between indigenous and ladina women. To reduce these disparities, it is necessary to understand how indigenous women's disadvantages in linguistic, socioeconomic or residential characteristics relate to their underutilization of reproductive health services. METHODS: Logistic regression analyses of a nationally representative sample of women aged 15-49 from the 2008-2009 National Survey of Maternal and Infant Health were used to estimate ethnic disparities in women's use of institutional prenatal care and delivery, and in met demand for modern contraceptives. Using predicted probabilities, we estimated the extent to which these disparities were attributable to a language barrier among indigenous women and to their disadvantage in selected socioeconomic and residential characteristics. RESULTS: The ethnic difference in use of institutional prenatal care was small; however, institutional delivery was far less common among indigenous women than among ladina women (36% vs. 73%), as was met need for modern contraceptives (49% vs. 72%). Not speaking Spanish accounted for the largest portion of these ethnic differentials. Indigenous women's poor education and rural residence made up smaller portions of the ethnic differential in modern contraceptive use than did their economic disadvantage. CONCLUSION: The large proportion of indigenous women who use institutional prenatal care suggests that further integrating the three services may increase their use of institutional delivery and modern contraceptives. Adding speakers of local Mayan languages to the staff of health facilities could also help increase use.