CFTR catalysis involves the binding and hydrolysis of ATP, which leads to conformational changes in the protein, allowing chloride ions to pass through the channel. The process can be broken down into several steps:
1. ATP Binding: CFTR has two nucleotide-binding domains (NBDs) where ATP binds. 2. Phosphorylation: The regulatory domain of CFTR must be phosphorylated by protein kinase A (PKA) to activate the channel. 3. Channel Opening: ATP binding induces dimerization of the NBDs, resulting in the opening of the chloride channel. 4. ATP Hydrolysis: Hydrolysis of ATP to ADP causes conformational changes that close the channel.
