
PFRMAT AL
TARGET T0124
AUTHOR 7023-8870-2129
METHOD ADDITIONAL INFORMATION
METHOD Unlike other Phospholipase C (PLC) isozymes, PLC beta enzymes contain a 
METHOD region of sequence homology of ~250 amino acids near the C-terminus. 
METHOD This region is involved in activation of the lipase activity of PLC beta 
METHOD by GTP-bound G alpha q subunits and in turn acts as a GTPase Activating 
METHOD Protein (GAP) for G alpha q. This C-terminal 250 amino acid domain contains 
METHOD no obvious homology to known structures. I have solved the 
METHOD structure of this C-terminal domain representing amino acids 
METHOD 880-1154 of a PLC beta isolated from turkey erythrocytes. 
METHOD Initially crystals from this construct diffracted poorly (~7 A), 
METHOD so a region spanning amino acids 946-978 was deleted. This 
METHOD region is highly variable among PLCs, is protease-sensitive 
METHOD and is a site for serine phosphorylation. The crystals were grown 
METHOD between pH 5.7 to 6.3 and are triclinic. I would like to withhold 
METHOD information about the oligomerization state at present as I 
METHOD feel this is one of the interesting aspects of this structure. 
METHOD 
METHOD Sequence similarity searches did not yield matches to
METHOD proteins of known structure. Secondary structure prediction
METHOD suggests a long continuous helix and the protein has 
METHOD elevated coiled-coil scores throughout the sequence.
METHOD However, it is unlikely to form an oligomeric coiled-coil 
METHOD structure. Based on the nature and distribution of scores
METHOD we identify 5 amphipathic helices that are predicted to 
METHOD form an antiparellel square 5 helix bundle. Helices 1 and 3
METHOD contain unusual heptad discontinuities that do not appear
METHOD compatible with a parellel coiled-coil structure.
MODEL  1
PARENT NONE
TER
END

