Structural studies on cellulases, pectinases and xylanases

The importance of plant cell walls in agriculture, food technology and human health is so large that considerable efforts are being made to understand the synthesis and breakdown of the complex carbohydrates which form the cell wall structure. In particular the last three years has seen the discovery of many of the tertiary structure of proteins involved in cell wall degradation. Initially there was an extensive classification based on amino acid homologies but the tertiary structures of the proteins has revealed surprising data about the structural homologies that are found between cellulases and xylanases. Although the structural data has possible reduced the usefulness of the earlier classification it has given much information on the evolutionary trends amongst these enzymes. Perhaps even more exciting has been the discovery that enzymes that modify pectin have a unique and unexpected structural motif. © 1996 Elsevier B.V. All rights reserved.