Cloning of two cDNAs encoding calnexin-like and calreticulin-like proteins from maize (Zea mays) leaves: identification of potential calcium-binding domains.

Two cDNAs encoding calnexin (Cln)-like and calreticulin (Crl)-like proteins have been isolated by immunoscreening of a maize leaf cDNA library. In the deduced amino acid (aa) sequences, several regions that are conserved for Cln and Crl proteins from all sources have been identified. These regions can be classified into two distinct motifs which are repeated four times each in Cln and three times each in Crl sequences. One of these motifs, containing a highly acidic 17-aa sequence, has high homology to a Ca(2+)-binding domain previously characterized in both Cln and Crl from mammalian tissues. Motifs for retention in endoplasmic reticulum (Crl) and for an integral membrane-spanning sequence (Cln) have also been identified.