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Oncomodulin and parvalbumin contain three EF-hands, of which the first is nonfunctional and unpaired. The helices of EF1 are antiparallel to each other. EF2 and EF3 are positioned similarly to the open conformation observed in Ca2+-CaM and Ca2+-TnC. The second helix of EF3 is one residue shorter than the standard used for all VGM calculations shown here, thus the corresponding value of omega is not valid. |
| EF-hand (helix residues) | N-terminal coordinate
of second helix |
theta | phi | omega |
| Ca2+-oncomodulin EF1 (11-18, 26-36) | (5.223, 9.046, 1.030) | 4.605 | -146.422 | 120 |
| Ca2+-oncomodulin EF2 (43-50, 60-70) | (7.737, -2.219, -8.656) | 65.646 | 105.167 | 59 |
| Ca2+-oncomodulin EF3 (82-89, 98-108) | (9.119, 2.274, -5.868) | 85.124 | 138.404 | N/A |
| EF-hand (helix residues) | N-terminal coordinate
of second helix |
theta | phi | omega |
| Ca2+-parvalbumin EF1 (11-18, 26-36) | (3.982, 8.944, 0.688) | 1.123 | 27.375 | 202 |
| Ca2+-parvalbumin EF2 (43-50, 60-70) | (6.974, -1.739, -8.562) | 66.453 | 109.104 | 50 |
| Ca2+-parvalbumin EF3 (82-89, 99-109) | (8.258, 3.337, -7.754) | 75.711 | 130.003 | 77 |
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Extracellular BM40's two EF-hands are positioned similarly to those of Ca2+-CaM, even though the interhelical loop of EF1 contains a one-residue insertion. The second helices of both EF-hands are shorter than the standard length used in VGM calculations; omega values are not valid. |
| EF-hand (helix residues) | N-terminal coordinate
of second helix |
theta | phi | omega |
| Ca2+-BM40 EF1 (214-221, 232-238) - shortened | (8.641, 0.604, -5.982) | 58.069 | 95.607 | N/A |
| Ca2+-BM40 EF2 (249-256, 266-272) - shortened | (8.476, -1.648, -5.724) | 66.180 | 90.040 | N/A |
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SCP contains four EF-hands, of which EF1, EF3 and EF4 bind Ca2+ in the structure shown; all SCPs bind Ca2+ at EF1 and EF3, and some bind at EF2 instead of EF4. The lack of Ca2+ ion at EF2 may be energetically unfavourable for the helical arrangement of the N-terminal domain, resulting in the unusual positions of EF1 and EF2; EF3 and EF4 are situated as in the open conformation of Ca2+-CaM. |
| EF-hand (helix residues) | N-terminal coordinate
of second helix |
theta | phi | omega |
| Ca2+-SCP EF1 (8-15, 25-35) | (6.740, -1.556, -8.773) | 118.878 | 122.951 | 44 |
| Ca2+-SCP EF2 (53-60, 70-80) | (13.854, -6.757, -3.241) | 119.042 | 94.194 | 336 |
| Ca2+-SCP EF3 (96-103, 113-123) | (9.032, -0.632, -6.391) | 71.754 | 95.531 | 98 |
| Ca2+-SCP EF4 (130-137, 147-157) | (8.015, 0.280, -6.978) | 75.699 | 107.499 | 100 |
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EH2 contains two EF-hands; only EF2 binds Ca2+. The length of the interhelical loop of EF1 is one residue shorter than the consensus sequence. Both EF-hands are similarly positioned as in the closed conformation. |
| EF-hand (helix residues) | N-terminal coordinate
of second helix |
theta | phi | omega |
| Ca2+-EH2 EF1 (17-24, 33-43) | (8.638, 0.302, -4.534) | 55.823 | 81.214 | 124 |
| Ca2+-EH2 EF2 (50-57, 67-77) | (7.517, 0.262, -6.289) | 37.803 | 104.741 | 78 |
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PLC-D1 consists of several domains, including a domain containing four EF-hands. EF1 and EF2 bind Ca2+, although EF1 is not shown as it is disordered in the structure. Collectively the EF-hand positions are not similar to either open or closed conformations; interestingly, similar interaction of the EF-hand domain with the C2 domain occurs in PLC-D1 as is observed in the Ca2+-CaM-CaMKII peptide complex. |
| EF-hand (helix residues) | N-terminal coordinate
of second helix |
theta | phi | omega |
| apo-PLC-D1 EF2 (181-188, 198-208) | (8.815, -1.082, -4.846) | 39.572 | 95.023 | 110 |
| apo-PLC-D1 EF3 (214-221, 230-240) | (7.769, -1.510, -7.733) | 67.074 | 90.840 | 103 |
| apo-PLC-D1 EF4 (251-258, 272-282) | (9.704, -0.679, -1.853) | 83.842 | 111.497 | 90 |
NB: values obtained using apo-CaM EF1 (as in refcam.pdb) as the reference EF-hand.