What is an EF protein?

The EF-hand consists of two alpha helices linked by a short loop region (usually about 12 amino acids) that usually binds calcium ions. EF-hands also appear in each structural domain of the signaling protein calmodulin and in the muscle protein troponin-C.

What is meant by an EF-hand?

The EF-hand is a diverse motif class consisting of 30 amino acids that fold into a helix-loop-helix structure. Its structure resembles a right hand fist, with the index finger and thumb extended. The index finger represents the N-terminal “E” helix and the thumb represents the C-terminal “F” helix.

What is the role of the EF-hand in STIM1?

These data indicate that the STIM1 canonical EF-hand motif tends to dimerize for functionality in solution and is responsible for sensing changes in [Ca2+]ER.

Does calmodulin have an EF-hand?

Calmodulin (CaM) is an EF-hand protein composed of two calcium (Ca2+)-binding EF-hand motifs in its N-domain (EF-1 and EF-2) and two in its C-domain (EF-3 and EF-4).

How is the leucine zipper formed and what is its function?

Leucine zipper is created by the dimerization of two specific alpha helix monomers bound to DNA. The leucine zipper is formed by amphipathic interaction between two ZIP domains. The ZIP domain is found in the alpha-helix of each monomer, and contains leucines, or leucine-like amino acids.

How many EF hands does calmodulin have?

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 amino acids are in leucine zipper?

Leucine zippers are α-helices that contain a leucine residue every seventh amino acid. This motif is found in many eukaryotic transcription factors. Zinc fingers consist of 25-30 amino acids surrounding a single zinc atom, which is coordinated by two cysteines, which are very close to short α-helices.

What holds a leucine zipper together?

Being hydrophobic, the leucines cause two adjacent alpha helices to be “zippered” together by hydrophobic interactions. On the end of each alpha helix is the DNA binding region which contains basic amino acids that form ionic bonds with the acidic DNA.

How does EF-hand bind calcium?

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).