Alternative Conformations of HIV-1 V3 Loops Mimic β Hairpins in Chemokines, Suggesting a Mechanism for Coreceptor Selectivity

AbstractThe V3 loop of the HIV-1 envelope glycoprotein gp120 is involved in binding to the CCR5 and CXCR4 coreceptors. The structure of an HIV-1MN V3 peptide bound to the Fv of the broadly neutralizing human monoclonal antibody 447-52D was solved by NMR and found to be a β hairpin. This structure of V3MN was found to have conformation and sequence similarities to β hairpins in CD8 and CCR5 ligands MIP-1α, MIP-1β, and RANTES and differed from the β hairpin of a V3IIIB peptide bound to the strain-specific murine anti-gp120IIIB antibody 0.5β. In contrast to the structure of the bound V3MN peptide, the V3IIIB peptide resembles a β hairpin in SDF-1, a CXCR4 ligand. These data suggest that the 447-52D-bound V3MN and the 0.5β-bound V3IIIB structures represent alternative V3 conformations responsible for selective interactions with CCR5 and CXCR4, respectively

What’s Going on in My Baby’s Mind? Mothers’ Executive Functions Contribute to Individual Differences in Maternal Mentalization During Mother-Infant Interactions

Maternal mentalization refers to a mother’s capacity to understand mental-states of herself and her child and to regard her child as a psychological agent. In mother-infant interactions, this capacity is commonly conceptualized as maternal mind-mindedness, which can be divided into two dimensions: appropriate and nonattuned interpretations of the infants’ mental-states. Appropriate mind-mindedness refers to interpretations that seem to be compatible with the infant’s behaviors, whereas the nonattuned mind-mindedness refers to noncompatible interpretations. The aim of this study was to investigate the cognitive mechanisms that contribute to mind-mindedness. Specifically, we investigated the role of executive functions in appropriate and nonattuned mind-mindedness, and the moderating roles of two infant-related factors, prematurity (as a stressful context) and child temperament (as a context of unpredictability and negative emotionality). To this end, mother-infant free play interactions were coded for mind-mindedness in a sample of 102 mothers and their 6-month-old infants (61 preterm, 41 full-term). When children were 66-months old, mothers completed cognitive tasks that assessed working memory updating, resistance to interference, response inhibition, and shifting. Appropriate mind-mindedness was positively associated with updating, and this link was stronger when infant temperament was rated as more difficult. Furthermore, among mothers of full-term infants, mothers’ resistance to interference was negatively associated with nonattuned mind-mindedness. This link was not evident in the stressful context of premature birth. Mothers’ response inhibition and shifting were not associated with either of the mind-mindedness dimensions. Implications on understanding variability in maternal mentalization during mother-infant interactions and the roles of executive functions in parenting are discussed

Supplementary Materials

Detailed description of EF task

What's going on in my baby's mind? Mothers' executive functions contribute to individual differences in maternal mentalization during mother-infant interactions.

Maternal mentalization refers to a mother's capacity to understand mental-states of herself and her child and to regard her child as a psychological agent. In mother-infant interactions, this capacity is commonly conceptualized as maternal mind-mindedness, which can be divided into two dimensions: appropriate and nonattuned interpretations of the infants' mental-states. Appropriate mind-mindedness refers to interpretations that seem to be compatible with the infant's behaviors, whereas nonattuned mind-mindedness refers to noncompatible interpretations. The aim of this study was to investigate the cognitive mechanisms that contribute to mind-mindedness. Specifically, we investigated the role of executive functions in appropriate and nonattuned mind-mindedness, and the moderating roles of two infant-related factors, prematurity (as a stressful context) and child temperament (as a context of unpredictability and negative emotionality). To this end, mother-infant free play interactions were coded for mind-mindedness in a sample of 102 mothers and their 6-month-old infants (61 preterm, 41 full-term). When children were 66-months old, mothers completed cognitive tasks that assessed working memory updating, resistance to interference, response inhibition, and shifting. Appropriate mind-mindedness was positively associated with updating, and this link was stronger when infant temperament was rated as more difficult. Furthermore, among mothers of full-term infants, mothers' resistance to interference was negatively associated with nonattuned mind-mindedness. This link was not evident in the stressful context of premature birth. Mothers' response inhibition and shifting were not associated with either of the mind-mindedness dimensions. Implications on understanding variability in maternal mentalization during mother-infant interactions and the roles of executive functions in parenting are discussed

Crystallization and X-ray analysis of human cytoplasmic phenylalanyl-tRNA synthetase

The crystallization and X-ray analysis of recombinant human cytosolic phenylalanyl-tRNA synthetase (hcPheRS) are reported. Diffraction data were collected to 3.3 Å resolution and the hcPheRS structure was determined by the molecular-replacement method using phase information derived from multiwavelength anomalous dispersion data