We have cloned the full coding cDNA sequence of chicken annexin V and of a mutant lacking 8 amino acid residues of the N-terminal tail for prokaryotic expression. Both proteins were synthesized in Escherichia coli upon induction with isopropyl thio-beta-D-galactoside, and were purified following two different protocols: one based on the ability of these proteins to interact reversibly with liposomes in the presence of calcium, and the other based on two sequential ion-exchange chromatographic steps. Spectroscopical analysis of recombinant annexin V revealed that binding of calcium did not change the circular dichroism spectra indicating no significant changes on the secondary structure; however, a conformational change affecting the exposition to the solvent of the tryptophan residue 187 was detected by analysis of fluorescence emission spectra. Recombinant annexin V binds with high affinity to collagen types II and X, and with lower affinity to collagen type I in a calcium-independent manner. Heat denaturing of collagen decreases this interaction while pepsin-treatment of collagen almost completely abolishes annexin V binding. Mutated annexin V interacts with collagen in a similar way as the nonmutated recombinant protein, indicating that the N-terminal tail of annexin V is not essential for collagen binding.

Chicken annexin V (anchorin CII) is a collagen binding, membrane-associated molecule with Ca" channel activity. Here we report on the coding sequences, promotor region, size and distribution of exons, and exon-intron junctions of the chicken annexin V gene. It is about 25 kb long and codes for 13 short exons between 50 and 581 bp length. Exon sizes and locations of splice sites are almost completely homologous to those of the human and mouse annexin II or pigeon annexin I genes, although there is only SO-60% homology in the sequence of the corresponding proteins. The four repeat structure and symmetry of the armexin V as evident from sequence and X-ray analysis studies is only partially reflected in this highly conserved exon dist~bution. In the first two repeats of chicken annexin V the exons correlate with protein domains ~n~ining one, two, or three a-helices, while in the repeats 3 and 4 exon junctions and o-helical domains do not correlate. The analysis of the promotor structure revealed the absence of a typical TATA-box, but a GC-rich region which may possibly promote transcription from several start sites.