High-resolution profiling of homing endonuclease binding and catalytic specificity using yeast surface display

Experimental analysis and manipulation of protein–DNA interactions pose unique biophysical challenges arising from the structural and chemical homogeneity of DNA polymers. We report the use of yeast surface display for analytical and selection-based applications for the interaction between a LAGLIDADG homing endonuclease and its DNA target. Quantitative flow cytometry using oligonucleotide substrates facilitated a complete profiling of specificity, both for DNA-binding and catalysis, with single base pair resolution. These analyses revealed a comprehensive segregation of binding specificity and affinity to one half of the pseudo-dimeric interaction, while the entire interface contributed specificity at the level of catalysis. A single round of targeted mutagenesis with tandem affinity and catalytic selection steps provided mechanistic insights to the origins of binding and catalytic specificity. These methods represent a dynamic new approach for interrogating specificity in protein–DNA interactions

The problem of constitutional legitimation: what the debate on electoral quotas tells us about the legitimacy of decision-making rules in constitutional choice

Proponents of electoral quotas have a ‘dependent interpretation’ of democracy, i.e. they have formed an opinion on which decision-making rules are fair on the basis of their prior approval of the outcomes these rules are likely to generate. The article argues that this position causes an irresolvable problem for constitutional processes that seek to legitimately enact institutional change. While constitutional revision governed by formal equality allows the introduction of electoral quotas, this avenue is normatively untenable for proponents of affirmative action if they are consistent with their claim that formal equality reproduces biases and power asymmetries at all levels of decision-making. Their critique raises a fundamental challenge to the constitutional revision rule itself as equally unfair. Without consensus on the decision-making process by which new post-constitutional rules can be legitimately enacted, procedural fairness becomes an issue impossible to resolve at the stage of constitutional choice. This problem of legitimation affects all instances of constitutional choice in which there are opposing views not only about the desired outcome of the process but also about the decision-making rules that govern constitutional choice

Female Representation but Male Rule? Party Competition and the Political Glass Ceiling

A large literature has studied the context that affects womens numerical representation, but few have moved beyond numbers to study the drivers of a gender gap in political influence among elected politicians. Using panel data for the careers of 35.000 Swedish municipal politicians over six election cycles we first document the said gender gap. Women are substantially less likely to be re-elected for office, which is the most important pre-condition for obtaining influential appointments. Turing to the determinants we find that supply factors, primarily family responsibilities, explain some of this gap. Meanwhile, demand factors such as experience, age, education and income do not. Finding that competition between political parties closes the gap, we argue that a negative bias against women among party selectors thrives in contexts where meritocracy is not enforced. Positive correlations between competition and measures of competence for elected politicians of both genders further support this conclusion