1P6E

STRUCTURE OF THE D55N MUTANT OF PHOSPHOLIPASE C FROM BACILLUS CEREUS IN COMPLEX WITH 1,2-DI-N-PENTANOYL-SN-GLYCERO-3-DITHIOPHOSPHOCHOLINE

Summary for 1P6E

• Entry DOI: 10.2210/pdb1p6e/pdb
• Related: 1AH7 1P5X 1P6D
• Descriptor: Phospholipase C, ZINC ION, 1,2-DI-N-PENTANOYL-SN-GLYCERO-3-DITHIOPHOSPHOCHOLINE, ... (4 entities in total)
• Functional Keywords: protein-phospholipid analogue complex, tri zn+2 metal core, hydrolase
• Biological source: Bacillus cereus
• Total number of polymer chains: 1
• Total formula weight: 29076.25

Authors

Antikainen, N.M.,Monzingo, A.F.,Franklin, C.L.,Robertus, J.D.,Martin, S.F. (deposition date: 2003-04-29, release date: 2003-09-30, Last modification date: 2023-08-16)

Primary citation

Antikainen, N.M.,Monzingo, A.F.,Franklin, C.L.,Robertus, J.D.,Martin, S.F.
Using X-ray crystallography of the Asp55Asn mutant of the phosphatidylcholine-preferring phospholipase C from Bacillus cereus to support the mechanistic role of Asp55 as the general base.
Arch.Biochem.Biophys., 417:81-86, 2003

PubMed Abstract: Because mutations of the ionizable Asp at position 55 of the phosphatidylcholine preferring phospholipase C from Bacillus cereus (PLC(Bc)) to a non-ionizable Asn generate a mutant enzyme (D55N) with 10(4)-fold lower catalytic activity than the wild-type enzyme, we tentatively identified Asp55 as the general base for the enzymatic reaction. To eliminate the alternate possibility that Asp55 is a structurally important amino acid, the X-ray structures of unbound D55N and complexes of D55N with two non-hydrolyzable substrate analogues have been solved and refined to 2.0, 2.0, and 2.3A, respectively. The structures of unbound wild-type PLC(Bc) and a wild-type PLC(Bc)-complex with a non-hydrolyzable substrate analogue do not change significantly as a result of replacing Asp55 with Asn. These observations demonstrate that Asp55 is not critical for the structural integrity of the enzyme and support the hypothesis that Asp55 is the general base in the PLC(Bc)-catalyzed hydrolysis of phospholipids.

PubMed: 12921783
DOI: 10.1016/S0003-9861(03)00343-6

Experimental method

X-RAY DIFFRACTION (2.3 Å)