Crystal structure of plant aspartic proteinase prophytepsin: inactivation and vacuolar targeting.
We determined at 2.3 A resolution the crystal structure of prophytepsin, a zymogen of a barley vacuolar aspartic proteinase. In addition to the classical pepsin-like bilobal main body of phytepsin, we also traced most of the propeptide, as well as an independent plant-specific domain, never before described in structural terms. The structure revealed that, in addition to the propeptide, 13 N-terminal residues of the mature phytepsin are essential for inactivation of the enzyme. Comparison of the plant-specific domain with NK-lysin indicates that these two saposin-like structures are closely related, suggesting that all saposins and saposin-like domains share a common topology. Structural analysis of prophytepsin led to the identification of a putative membrane receptor-binding site involved in Golgi-mediated transport to vacuoles.
Protein Structure Section, Macromolecular Structure Laboratory, ABL-Basic Research Program, NCI-Frederick Cancer Research and Development Center, Frederick, MD 21702, USA.
J
J
Kervinen
G J
GJ
Tobin
J
J
Costa
D S
DS
Waugh
A
A
Wlodawer
A
A
Zdanov
D000595:Amino Acid Sequence; D016282:Aspartic Acid Endopeptidases / Q000737:chemistry* / Q000378:metabolism; D001692:Biological Transport; D002403:Cathepsins / Q000737:chemistry* / Q000378:metabolism; D018360:Crystallography, X-Ray; D004220:Disulfides / Q000737:chemistry; D004583:Electrons; D004789:Enzyme Activation; D004792:Enzyme Precursors / Q000737:chemistry* / Q000378:metabolism; D006023:Glycoproteins / Q000737:chemistry; D006056:Golgi Apparatus / Q000378:metabolism; D001467:Hordeum / Q000166:cytology / Q000201:enzymology* / Q000378:metabolism; D006860:Hydrogen Bonding; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D011510:Proteolipids / Q000737:chemistry; D011663:Pulmonary Surfactants / Q000737:chemistry; D011956:Receptors, Cell Surface / Q000378:metabolism; D049231:Saposins; D017386:Sequence Homology, Amino Acid; D014617:Vacuoles / Q000201:enzymology*
D004220:Disulfides; D004792:Enzyme Precursors; D006023:Glycoproteins; C093238:NK-lysin; D011510:Proteolipids; D011663:Pulmonary Surfactants; D011956:Receptors, Cell Surface; D049231:Saposins; D002403:Cathepsins; D016282:Aspartic Acid Endopeptidases; C109797:phytepsin