What is meant by an EF hand?
What is meant by an EF hand?
EF hand. 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.
What is an EF domain?
The adjacent end of α-spectrin, called the EF domain, is calmodulin-like, with calcium-dependent and calcium-independent EF hands. The severely anemic sph(1J)/sph(1J) mouse has very fragile red cells and lacks the last 13 amino acids in the EF domain, implying that the domain is critical for skeletal integrity.
How many EF hands in calmodulin?
two EF hand pairs
Calmodulin (CaM) is a cytosolic Ca2+-binding protein that serves as a control element for many enzymes. It consists of two globular domains, each containing two EF hand pairs capable of binding Ca2+, joined by a flexible central linker region.
What do calcium binding proteins do?
Calcium binding proteins have specific domains that bind to calcium and are known to be heterogeneous. One of the functions of calcium binding proteins is to regulate the amount of free (unbound) Ca2+ in the cytosol of the cell. The regulation of Ca2+ is called calcium homeostasis.
What is the EF loop?
The EF hand is a helix–loop–helix structural domain or motif found in a large family of calcium-binding proteins. The EF-hand motif contains a helix–loop–helix topology, much like the spread thumb and forefinger of the human hand, in which the Ca2+ ions are coordinated by ligands within the loop.
How does calmodulin bind calcium?
Calmodulin is a small dumbbell-shaped protein composed of two globular domains connected together by a flexible linker. Each end binds to two calcium ions. PDB entry 3cln , shown here, has all four sites filled with calcium ions and the linker has formed a long alpha helix separating the two calcium-binding domains.
What is FX on an amplifier?
An FX Loop is essential an insert point in your amplifier circuit that allows you to insert a piece of gear after the preamp circuit, but before the power amp circuit. Some guitar players are happy to run everything into the front end of the amp, and others prefer to insert certain effects types into the loop.
What does FX loop do?
An effects loop is an input/output that allows you to place effects between the pre-amp section of the guitar – where it gets its tone and the power section of the amplifier – where it amplifies the sound. This means that your pre-amp can go anywhere in the signal chain rather than having to be the last stop.
Does skeletal muscle have troponin?
Troponins are the protein filament components of the contractile cardiac and skeletal muscles, but which are not present in smooth muscle [43].
What is the structure of the EF-hand motif?
The EF-hand motif contains a helix-loop-helix topology, much like the spread thumb and forefinger of the human hand, in which the Ca 2+ ions are coordinated by ligands within the loop.
What is the function of EF hands?
EF hands bind Ca 2+, 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.
What is the function of the EF-hand domain?
Proteins containing EF-hands can be grouped into two functional categories—regulatory and structural. The binding of calcium to regulatory EF-hand domain—containing proteins induces a conformational change that is transmitted to their target proteins, often catalyzing enzymatic reactions.
What is at the x axis of the EF-hand loop?
The residue at the –X axis coordinates the Ca 2+ ion through a bridged water molecule. The EF-hand loop has a bidentate ligand (Glu or Asp) at axis –Z. Pseudo EF-hands exclusively found in the N-termini of S100 and S100-like proteins.
