Bidirectional Loop Engineering Uncovers a Structural Determinant for Product Specificity in GH46 Family Chitosanases.
A bidirectional loop-engineering strategy is employed to decipher the function of a conserved loop (XDXXP) in GH46 chitosanases and reveals that the loop modulates the geometry, electrostatics, and hydrophilicity of the substrate-binding cleft, thereby influencing substrate recognition and product specificity.