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User:Alice Harmon/EF Hand
From Proteopedia
(New page: EF-hands are calcium-binding motifs found in hundreds of proteins. They bind calcium ions with high affinity (K<sub>d</sub>s are in the micromolar range) and selectivity, and this property...) |
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Below are EF-hands found in parvalbumin, calmodulin, and calcium-dependent protein kinase. | Below are EF-hands found in parvalbumin, calmodulin, and calcium-dependent protein kinase. | ||
| + | |||
| + | {| | ||
| + | | <applet load='3HX4' size='400' frame='true' align='left' caption='3hx4 - active TgCDPK1' scene = 'User:Alice_Harmon/Sandbox_2/55/559103/Holo-akinase/2' /><Br>'''3HX4'''<Br><scene name='56/562354/Cdpk_ef_hand_pair/2'>1. Pair of EF hands</scene><br><scene name='56/562354/Cdpk_ef_iv/1'>2. EF Hand IV</scene><br><scene name='56/562354/Cdpk_ef_iv/2'>3. Calcium-binding ligands</scene> | ||
| + | | <applet load='1prw' size='300' frame='true' align='right' caption='1prw - Bovine calmodulin' scene='' /><Br>'''1prw''' <Br> | ||
| + | | <applet load='4cpv' size='300' frame='true' align='right' caption='4cpv - Carp parvalbumin' scene='' /><Br>'''4cpv''' <Br> | ||
| + | |} | ||
Revision as of 14:35, 20 September 2013
EF-hands are calcium-binding motifs found in hundreds of proteins. They bind calcium ions with high affinity (Kds are in the micromolar range) and selectivity, and this property allows EF-hand proteins to sense changes in intracellular calcium. In unstimulated cells cellular free calcium concentrations [Ca2+]c are in the nanomolar range (~10 nM in animal cells and ~200 nM in plant cells), and EF-hands are generally unoccupied by Ca2+. Upon stimulation, Ca2+ enters the cytosol from either outside the cell or from internal organelles, and [Ca2+]c rises to the micromolar range. EF-hands bind Ca2+, and this binding causes a conformational change that alters the activity of the protein.
The name EF-hand originated from the first such structure to be described, which was in the protein parvalbumin. In this protein calcium is bound by a helix-loop-helix structure that is formed by the E and F helices (letters assigned to helices in the order that they occur starting at the N-terminus). See the annotated protein sequence for carp parvalbumin here [1].
Below are EF-hands found in parvalbumin, calmodulin, and calcium-dependent protein kinase.
3HX4 |
1prw |
4cpv |
