Peptides eluted from the MHC class I Kd molecule are generally nonamers that display a strong preference for Tyr in position 2 and Ile or Len in position 9. We investigated the binding ability of several synthetic peptides which did not fit this consensus motif. In our peptides, Tyr2 was substituted by other amino acids, i.e. Len, Ile or Met. These peptides were variants of the 252–260 Kd‐restricted peptide SYIPSAEKI derived from the Plasmodium berghei circumsporozoite protein. They bound to purified Kd molecules in vitro with intermediate affinity. One of them was tested for in vivo stimulation of T cells and induced a cytotoxic response. These results demonstrate the importance of binding motif refinement to discover new binding characteristics and new ligands such as low‐affinity peptides.