Multi-interface domain illustration.

<p>Domain <i>a</i> of protein <i>A</i> interacting with domain <i>b</i> of protein <i>B</i> produces interface <i>a–b</i> on domain <i>a</i>, and domain <i>a</i> binding to protein <i>C</i> generates interface <i>a–c</i> on domain <i>a</i>. Interfaces <i>a–b</i> and <i>a–c</i> are distinguishable on domain <i>a</i>, thus domain <i>a</i> is a multi-interface domain.