Plasmodium falciparum AMA-1 erythrocyte binding peptides implicate AMA-1 as erythrocyte binding protein

The role of AMA-1 during merozoite invasion has not yet been determined. Ho wever, reported experimental evidence suggests that this protein can be use d, in particular as erythrocyte-binding protein, since, Fab fragments again st this protein are able to block merozoite invasion. Using a previously de scribed methodology, eight peptides with high binding activity to human ery throcyte, scattered along the different domains and having around 130 nM af finity constants, were identified in the Plasmodium falciparum AMA-1 protei n. Their binding activity was sialic acid independent. Some of these peptid es showed homology with the erythrocyte binding domains of one of the apica l. organelle protein family, MAEBL, identified in rodent malarial parasites . One of these peptides shares amino acid sequence with a previously report ed B-cell epitope which induces antibodies to block parasite growth. The cr itical residues were identified for erythrocyte binding conserved peptides 4313 (DAEVAGTQYRLPSGKCPVFG), 4321 (VVDNWEKVCPRKNLQNAKFG), 4325 (MIKSAFLPTGA FKADRYKSH) and 4337 (WGEEKRASHTTPVLMEKPYY). AU conserved peptides were able to block merozoite invasion of new RBC and development,suggesting that the se peptides are involved in P. falciparum invasion. (C) 2000 Elsevier Scien ce Ltd. All rights reserved.