Carbohydrate binding specificity. AE in polyacrylamide gels polymerized in the presence of no substrate, 0.5 mg xyloglucan/ml, 1.0 mg xylan/ml, 0.5 mg lichenan/ml or 1.0 mg laminarin/ml. The arrow indicates the direction of migration in the gels. The evolved modules XG-34/1-X and XG-34/2-VI exhibited efficient binding to xyloglucan while XG-34/2-I bound slightly better than XG-34 and CBM4-2. The evolved clones do not show affinity for the other polysaccharides indicating that the specificity for xyloglucan was retained during the affinity maturation process. The first lane contains a kaleidoscopic protein-ladder to monitor gel migration and in the last lane an evolved xylan-specific CBM, X-2  serves as a control.