Three possible topics:
https://en.wikipedia.orgview_html.php?sq=Qlik&lang=&q=Rossmann_fold
https://en.wikipedia.orgview_html.php?sq=Qlik&lang=&q=Pyruvate_dehydrogenase
https://en.wikipedia.orgview_html.php?sq=Qlik&lang=&q=Substrate_(chemistry)