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Structural insights into the processivity of endopolygalacturonase I from Aspergillus niger
Author(s) -
van Pouderoyen Gertie,
Snijder Harm J,
Benen Jacques A.E,
Dijkstra Bauke W
Publication year - 2003
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(03)01221-3
Subject(s) - processivity , aspergillus niger , cleavage (geology) , chemistry , residue (chemistry) , stereochemistry , substrate (aquarium) , enzyme , active site , binding site , biochemistry , biology , polymerase , paleontology , ecology , fracture (geology)
Endopolygalacturonase I is a processive enzyme, while the 60% sequence identical endopolygalacturonase II is not. The 1.70 Å resolution crystal structure of endopolygalacturonase I reveals a narrowed substrate binding cleft. In addition, Arg96, a residue in this cleft previously shown to be critical for processivity, interacts with the substrate mimics glycerol and sulfate in several well‐defined conformations in the six molecules in the asymmetric unit. From this we conclude that both Arg96 and the narrowed substrate binding cleft contribute to retaining the substrate while it moves through the active site after a cleavage event has occurred.