AN UNUSUAL BURIED POLAR CLUSTER IN A FAMILY OF FUNGAL LIPASES

The stability of globular proteins arises largely from the burial of n on-polar amino acids in their interior. These residues are efficiently packed to eliminate energetically unfavorable cavities. Contrary to t hese observations, high resolution X-ray crystallographic analyses of four homologous lipases from filamentous fungi reveal an alpha/beta fo ld which contains a buried conserved constellation of charged and pola r side chains with associated cavities containing ordered water molecu les. It is possible that this structural arrangement plays an importan t role in interfacial catalysis.