Info

ef-1 (9-39) iaefkeafslfdkîgdgîittkçlgtvmrslgqnpt ef-2 (45-75) eaelçdm inevdadgngtipf psfltmmahkmkdtds ef-3(32-112) eeeireafrvfdkdgngyigaaçlrhvmthlgekjt ef-4 (110-146) deevdemireadidgdgqvnï eifvqhmtak

Figure 3. The locations of the residues used for the construction of the bidentate ligand in calmodulin are labeled with a star. Residues used for calcium-binding ligands are in bold. The sequence positions and relative orientations of the ligand residues are labeled above the amino acid sequences.

Identification of classic EF-hand sites in calmodulin

With the descriptions discussed above, 3772 potential sites are constructed in the calmodulin. Their locations in the primary sequence are shown in Fig. 3. When the water position is specifically placed on the top of the plane of the pentagonal geometry, the number of the constructed sites is reduced about 70%. The majority of the constructed sites are located at the four calcium binding loops while only four anchor sites are placed out of the calcium binding loops. Besides Glu at the loop position 12, which is used as the bidentate ligands for natural sites 1 to 4, loop positions 2, 8 and 9 are also used to place the bidentate Glu (anchor), where the loop position 9 in the natural calcium binding sites is often occupied by an oxygen ligand from a bridged water molecule (Linse & Forsen, 1995).

Table. L. The CA-O lengths of the natural and relocated calcium-binding sites.

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