hSKCa3: no association of the polymorphic CAG repeat with bipolar affective disorder and schizophrenia.

hSKCa3 is a neuronal small conductance calcium-activated potassium channel, which contains a polyglutamine tract, encoded by a polymorphic CAG repeat in the gene. Since an association between longer alleles of this CAG repeat and bipolar disorder or schizophrenia has been reported, we genotyped the polymorphic CAG repeat in 91 German family trios of patients with bipolar disorder I and used the transmission disequilibrium test (TDT) to test for association. Applying a dichotomized model (< or = 19 or > 19 CAG triplets), we found no evidence for an association of longer alleles with bipolar disorder (TDT = 0.

Why is DsbA such an oxidizing disulfide catalyst?

DsbA, a member of the thioredoxin family of disulfide oxidoreductases, acts in catalyzing disulfide bond formation by donating its disulfide to newly translocated proteins. We have found that the two central residues within the active site Cys-30-Pro-31-His-32-Cys-33 motif are critical in determining the exceptional oxidizing power of DsbA. Mutations that change these two residues can alter the equilibrium oxidation potential of DsbA by more than 1000-fold.