Substrate binding to the cytochrome P450 OleP is coupled to a large open-to-closed transition that remodels the active site. minimizing its exposure to the external solvent. When the aglycone substrate binds. a small empty cavity is formed between the I and G helices. https://www.roneverhart.com/Turbosound-TS-18SW700-8A-18-Low-Frequency-Loudspeaker-p31480/