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Although DNA flexibility is known to play an important role in DNA–protein interactions, the importance of protein flexibility is less well understood. Here, we show that protein dynamics are important in DNA recognition using the well-characterized human papillomavirus (HPV) type 6 E2 protein as a model system. We have compared the DNA binding properties of the HPV 6 E2 DNA binding domain (DBD) and a mutant lacking two C-terminal leucine residues that form part of the hydrophobic core of the protein. Deletion of these residues results in increased specific and non-specific DNA binding and an overall decrease in DNA binding specificity. Using 15N NMR relaxation and hydrogen/deuterium exchange, we demonstrate that the mutation results in increased flexibility within the hydrophobic core and loop regions that orient the DNA binding helices. Stopped-flow kinetic studies indicate that increased flexibility alters DNA binding by increasing initial interactions with DNA but has little or no effect on the structural rearrangements that follow this step. Taken together these data demonstrate that subtle changes in protein dynamics have a major influence on protein–DNA interactions.

This article studies bank failures in twenty-one emerging market countries in the 1990s. By using a competing risk hazard model for bank survival, we show that a government is less likely to take over or close a failing bank if the banking system is weak. This Too-Many-to-Fail effect is robust to controlling for macroeconomic factors, financial crises, the Too-Big-to-Fail effect, domestic financial development, and concerns due to systemic risk and information spillovers. The article also shows that the Too-Many-to-Fail effect is stronger for larger banks and when there is a large government budget deficit. The Author 2009. Published by Oxford University Press on behalf of The Society for Financial Studies. All rights reserved. For Permissions, please e-mail: journals.permissions@oxfordjournals.org., Oxford University Press.

This paper studies large private banks in 21 major emerging markets in the 1990s. It first demonstrates that bank failures are very common in these countries: about 25 percent of these banks failed during the seven-year sample period. The paper also shows that political concerns play a significant role in delaying government interventions to failing banks. Failing banks are much less likely to be taken over by the government or to lose their licenses before elections than after. This result is robust to controlling for macroeconomic and bank-specific factors, a new party in power, early elections, outstanding loans from the IMF, as well as country-specific, time-independent factors. This finding implies that much of the within-country clustering in emerging market bank failures is directly due to political concerns.