No abstract

Background:The protein dimerization cofactor of HNF-1 (DCoH1)/pterin-carbinolamine dehydratase (PCD) accomplishes two unrelated activities, forming two complexes with the same interface. Results: The DCoH1 homotetramer is kinetically trapped; a single mutation in the interface increases the unfolding rate 10 9 -fold. Conclusion: Kinetic regulation allows DCoH to assume two unrelated functions. Significance: Mutations excluding water from interfaces represent kinetic "hot spots," dramatically affecting dissociation rates.