Extending the cellulosome paradigm: the modular Clostridium thermocellum cellulosomal serpin PinA is a broad-spectrum inhibitor of subtilisin-like proteases.

Clostridium thermocellum encodes a cellulosomal, modular, and thermostable serine protease inhibitor (serpin), PinA. PinA stability but not inhibitory activity is affected by the Fn(III) and Doc(I) domains, and PinA is a broad inhibitor of subtilisin-like proteases and may play a key role in protecting the cellulosome from protease attack.