Adsorbate-induced restructuring of transition metal surfaces and those of transition metal clusters embedded in metalloproteins has been shown to be a dominant phenomenon by LEED surface crystallography and X-ray crystallography studies, respectively. The restructuring is thermodynamically driven and is more facile for low-coordination metal sites (surface defects, steps and kinks, and nanoclusters). Dynamic restructuring of catalytically active transition metal sites may occur on the time scale of catalytic turnover or faster. The structural flexibility of transition metal surfaces and clusters embedded in enzymes could provide for seamless evolutionary changes of catalytic chemistry from inorganic to more complex and selective bio-organic systems.