Structural requirements of phosphatidylinositol-specific phospholipase C delta 1 for enzyme activity.
Phosphatidylinositol-specific phospholipase C delta 1 isozyme of phosphoinositol-specific phospholipase C has been used for studies of structural requirements for the catalytic function. The enzyme was expressed in a bacterial system and purified to homogeneity. Using a combination of deletion mutant analysis and limited proteolysis, it was found that the large proportion of the molecule participated in formation of a catalytic domain (residues 139-756); it included regions of high and low conservation with other phospholipase-C molecules. These studies also showed that the residues spanning regions of conservation, designated as X and Y, were exposed and highly susceptible to proteolysis by trypsin. Two of the fragments resulting from the cleavage (30 kDa and 40 kDa) interacted and, under non-denaturing conditions, formed a protein of 70 kDa.
Chester Beatty Laboratories, London, England.
M V
MV
Ellis
A
A
Carne
M
M
Katan
D000595:Amino Acid Sequence; D015870:Gene Expression; D006868:Hydrolysis; D008969:Molecular Sequence Data; D009154:Mutation; D010446:Peptide Fragments / Q000737:chemistry; D043265:Phosphatidylinositol Diacylglycerol-Lyase; D054801:Phosphoinositide Phospholipase C; D010727:Phosphoric Diester Hydrolases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D011487:Protein Conformation
D010446:Peptide Fragments; D010727:Phosphoric Diester Hydrolases; D054801:Phosphoinositide Phospholipase C; D043265:Phosphatidylinositol Diacylglycerol-Lyase