TY - JOUR
T1 - Substrate specificity of the Plasmodium falciparum glycosylphosphatidylinositol biosynthetic pathway and inhibition by species-specific suicide substrates
AU - Smith, Terry K.
AU - Gerold, Peter
AU - Crossman, Arthur
AU - Paterson, Michael J.
AU - Borissow, Charles N.
AU - Brimacombe, John S.
AU - Ferguson, Michael A. J.
AU - Schwarz, Ralph T.
PY - 2002/10/15
Y1 - 2002/10/15
N2 - The substrate specificities of the early glycosylphosphatidylinositol biosynthetic enzymes of Plasmodium were determined using substrate analogues of D-GlcNalpha1-6-D-myo-inositol-1-HPO4-sn-1,2-dipalmitoylglycerol (GlcN-PI). Similarities between the Plasmodium and mammalian (HeLa) enzymes were observed. These are as follows: (i) The presence and orientation of the 2'-acetamido/amino and 3'-OH groups are essential for substrate recognition for the de-N-acetylase, inositol acyltransferase, and first mannosyltransferase enzymes. (ii) The 6'-OH group of the GlcN is dispensable for the de-N-acetylase, inositol acyltransferase, all four of the mannosyltransferases, and the ethanolamine phosphate transferase. (iii) The 4'-OH group of GlcNAc is not required for recognition, but substitution interferes with binding to the de-N-acetylase. The 4'-OH group of GlcN is essential for the inositol acyltransferase and first mannosyltransferase. (iv) The carbonyl group of the natural 2-O-hexadecanyl ester of GlcN-(acyl)PI is essential for substrate recognition by the first mannosyltransferase. However, several differences were also discovered: (i) Plasmodium-specific inhibition of the inositol acyltransferase was detected with GlcN[L]-PI, while GlcN-(2-O-alkyl)PI weakly inhibited the first mannosyltransferase in a competitive manner. (ii) The Plasmodium de-N-acetylase can act on analogues containing N-benzoyl, GalNAc, or betaGlcNAc whereas the human enzyme cannot. Using the parasite specificity of the later two analogues with the known nonspecific de-N-acetylase suicide inhibitor [Smith, T. K., et al. (2001) EMBO J. 20, 3322-3332], GalNCONH(2)-PI and GlcNCONH(2)-beta-PI were designed and found to be potent (IC50 similar to0.2 muM), Plasmodium-specific suicide substrate inhibitors. These inhibitors could be potential lead compounds for the development of antimalaria drugs.
AB - The substrate specificities of the early glycosylphosphatidylinositol biosynthetic enzymes of Plasmodium were determined using substrate analogues of D-GlcNalpha1-6-D-myo-inositol-1-HPO4-sn-1,2-dipalmitoylglycerol (GlcN-PI). Similarities between the Plasmodium and mammalian (HeLa) enzymes were observed. These are as follows: (i) The presence and orientation of the 2'-acetamido/amino and 3'-OH groups are essential for substrate recognition for the de-N-acetylase, inositol acyltransferase, and first mannosyltransferase enzymes. (ii) The 6'-OH group of the GlcN is dispensable for the de-N-acetylase, inositol acyltransferase, all four of the mannosyltransferases, and the ethanolamine phosphate transferase. (iii) The 4'-OH group of GlcNAc is not required for recognition, but substitution interferes with binding to the de-N-acetylase. The 4'-OH group of GlcN is essential for the inositol acyltransferase and first mannosyltransferase. (iv) The carbonyl group of the natural 2-O-hexadecanyl ester of GlcN-(acyl)PI is essential for substrate recognition by the first mannosyltransferase. However, several differences were also discovered: (i) Plasmodium-specific inhibition of the inositol acyltransferase was detected with GlcN[L]-PI, while GlcN-(2-O-alkyl)PI weakly inhibited the first mannosyltransferase in a competitive manner. (ii) The Plasmodium de-N-acetylase can act on analogues containing N-benzoyl, GalNAc, or betaGlcNAc whereas the human enzyme cannot. Using the parasite specificity of the later two analogues with the known nonspecific de-N-acetylase suicide inhibitor [Smith, T. K., et al. (2001) EMBO J. 20, 3322-3332], GalNCONH(2)-PI and GlcNCONH(2)-beta-PI were designed and found to be potent (IC50 similar to0.2 muM), Plasmodium-specific suicide substrate inhibitors. These inhibitors could be potential lead compounds for the development of antimalaria drugs.
U2 - 10.1021/bi020351l
DO - 10.1021/bi020351l
M3 - Article
SN - 0006-2960
VL - 41
SP - 12395
EP - 12406
JO - Biochemistry
JF - Biochemistry
IS - 41
ER -