Ca2+-independent binding of anionic phospholipids by phospholipase C δ1 EF-hand domain.
Recombinant EF-hand domain of phospholipase C δ1 has a moderate affinity for anionic phospholipids in the absence of Ca(2+) that is driven by interactions of cationic and hydrophobic residues in the first EF-hand sequence. This region of PLC δ1 is missing in the crystal structure. The relative orientation of recombinant EF with respect to the bilayer, established with NMR methods, shows that the N-terminal helix of EF-1 is close to the membrane interface. Specific mutations of EF-1 residues in full-length PLC δ1 reduce enzyme activity but not because of disturbing partitioning of the protein onto vesicles. The reduction in enzymatic activity coupled with vesicle binding studies are consistent with a role for this domain in aiding substrate binding in the active site once the protein is transiently anchored at its target membrane.
From the Department of Chemistry, Boston College, Chestnut Hill, Massachusetts 02467 and.
Jingfei
J
Cai
Su
S
Guo
Jon W
JW
Lomasney
Mary F
MF
Roberts
D000818:Animals; D002118:Calcium / Q000737:chemistry / Q000378:metabolism; D020134:Catalytic Domain; D008051:Lipid Bilayers / Q000737:chemistry* / Q000378:metabolism; D009154:Mutation; D019906:Nuclear Magnetic Resonance, Biomolecular; D054803:Phospholipase C delta / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D010743:Phospholipids / Q000737:chemistry* / Q000378:metabolism; D011485:Protein Binding / Q000502:physiology; D017433:Protein Structure, Secondary; D051381:Rats; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
D008051:Lipid Bilayers; D010743:Phospholipids; D011994:Recombinant Proteins; D054803:Phospholipase C delta; C518026:Plcd1 protein, rat; D002118:Calcium
Enzymes; Glycerophospholipid; Membrane Enzymes; NMR; Phospholipase C; Phospholipid Vesicle; Site-directed Mutagenesis