Exploring Leishmania major inositol phosphorylceramide synthase (LmjIPCS): insights into the ceramide binding domain.
The synthesis of set of ceramide analogues exploring hydrophobicity in the acyl chains and the degree and nature of hydroxylation is described. These have been assayed against the parasitic protozoan enzyme LmjIPCS. These studies showed that whilst the C-3 hydroxyl group was not essential for turnover it provided enhanced affinity. Reflecting the membrane bound nature of the enzyme a long (C(13)) hydrocarbon ceramide tail was necessary for both high affinity and turnover. Whilst the N-acyl chain also contributed to affinity, analogues lacking the amide linkage functioned as competitive inhibitors in both enzyme and cell-based assays. A model that accounts for this observation is proposed.
Centre for Bioactive Chemistry, Biophysical Sciences Institute, Department of Chemistry and School of Biological Sciences, Durham University, Science Laboratories, South Road, Durham, UK DH1 3LE.
John G
JG
Mina
Jackie A
JA
Mosely
Hayder Z
HZ
Ali
Paul W
PW
Denny
Patrick G
PG
Steel
D000595:Amino Acid Sequence; D002518:Ceramides / Q000737:chemistry* / Q000378:metabolism; D006602:Hexosyltransferases / Q000737:chemistry* / Q000378:metabolism; D018320:Leishmania major / Q000201:enzymology*; D008969:Molecular Sequence Data; D011485:Protein Binding; D016415:Sequence Alignment
D002518:Ceramides; D006602:Hexosyltransferases; C088714:phosphatidylinositol-ceramide phosphoinositol transferase