1p6e
From Proteopedia
STRUCTURE OF THE D55N MUTANT OF PHOSPHOLIPASE C FROM BACILLUS CEREUS IN COMPLEX WITH 1,2-DI-N-PENTANOYL-SN-GLYCERO-3-DITHIOPHOSPHOCHOLINE
Structural highlights
FunctionPHLC_BACCE Required, with sphingomyelinase, to effect target cell lysis (hemolysis). Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedBecause 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. 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.,Antikainen NM, Monzingo AF, Franklin CL, Robertus JD, Martin SF Arch Biochem Biophys. 2003 Sep 1;417(1):81-6. PMID:12921783[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. Loading citation details.. Citations No citations found See AlsoReferences
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