displayed: apo-calbindin (1CLB),
apo-calcyclin (2CNP)
and apo-S100B (1B4C)
EF-hands in green; Ca2+-bound
calbindin (1B1G),
Ca2+-bound calcyclin (refined structure from WJ Chazin)
and Ca2+-S100B (1QLK)
EF-hands in cyan.
|
EF-hands of these S100 proteins in both Ca2+-free and Ca2+-loaded forms exhibit similar conformations, given by the small ranges of theta and phi. The exceptions are EF2 of calcyclin and S100B, the helices of which are unusually positioned in the Ca2+-free state: in fact, helix 1 (here in white) is the one that undergoes a significant change back to a more 'typical' S100 EF-hand arrangement. The second helix of these EF-hands are involved in the dimer interface. Calbindin D9k is the only known monomeric and most evolutionarily distant member of the S100 subfamily of proteins. The EF-hands undergo virtually no structural change upon binding Ca2+. |
| EF-hand (helix residues) | N-terminal coordinate
of second helix |
theta | phi | omega |
| apo-calbindin EF1 (6-13, 25-35) | (7.926, -2.885, -6.177) | 58.259 | 79.806 | 125 |
| apo-calbindin EF2 (46-53, 63-73) | (9.086, 0.317, -7.141) | 65.415 | 78.504 | 121 |
| Ca2+-calbindin EF1 (6-13, 25-35) | (8.998, -2.243, -6.131) | 49.213 | 81.989 | 131 |
| Ca2+-calbindin EF2 (46-53, 63-73) | (6.531, 1.388, -8.001) | 58.988 | 95.132 | 55 |
| EF-hand (helix residues) | N-terminal coordinate
of second helix |
theta | phi | omega |
| apo-calcyclin EF1 (12-19, 31-41) | (9.885, 0.000, -4.697) | 54.036 | 100.717 | 117 |
| apo-calcyclin EF2 (53-60, 70-80) | (-12.870, 6.843, -0.710) | 31.980 | -57.226 | 350 |
| Ca2+-calcyclin EF1 (12-19, 31-41) | (5.752, -2.805, -8.933) | 76.470 | 33.889 | 128 |
| Ca2+-calcyclin EF2 (53-60, 70-80) | (4.333, 6.424, -6.886) | 40.642 | 146.315 | 38 |
| EF-hand (helix residues) | N-terminal coordinate
of second helix |
theta | phi | omega |
| apo-S100B EF1 (10-17, 29-39) | (11.975, -3.434, -5.700) | 55.185 | 90.120 | 127 |
| apo-S100B EF2 (53-60, 70-80) | (7.805, 10.742, -3.878) | 17.254 | -112.440 | 90 |
| Ca2+-S100B EF1 (10-17, 29-39) | (9.615, -2.220, -6.311) | 54.513 | 77.720 | 111 |
| Ca2+-S100B EF2 (53-60, 70-80) | (10.155, -4.103, -6.192) | 74.322 | 90.619 | 93 |
| EF-hand (helix residues) | N-terminal coordinate
of second helix |
theta | phi | omega |
| p11 EF1 - cannot bind Ca2+ (11-18, 27-37) | (8.960, -1.259, -6.298) | 47.761 | 82.862 | 114 |
| p11 EF2 - cannot bind Ca2+ (51-58, 68-78) | (9.251, 3.185, -5.069) | 56.329 | 108.822 | 81 |
p11 PDB file: 1A4P
| EF-hand (helix residues) | N-terminal coordinate
of second helix |
theta | phi | omega |
| Ca2+-psoriasin EF1 (12-19, 29-39) | (8.339, 2.079, -5.471) | 40.156 | 87.133 | 18 |
| Ca2+-psoriasin EF2 (54-61, 71-81) | (8.859, 1.883, -6.220) | 48.152 | 98.126 | 81 |
Psoriasin PDB file: 1PSR
NB: values obtained using apo-CaM EF1 (as in refcam.pdb) as the reference EF-hand.