The 1,3(4)-b-d-glucanases of glycoside hydrolase family 16 provide useful examples of versatile yet specific protein–carbohydrate interactions. In the present study, we report the X-ray structures of the 1,3(4)-b-d-glucanase Phanerochaete chrysosporiumLaminarinase 16A in complex withb-glucan products from laminarin ( A˚ ) and lichenin ( A ˚ ) hydrolysis. The G6G3G3G glucan, in complex with the enzyme, showed ab-1,6 branch in the acceptor site.