Chloride Intracellular Channel Protein 2: Difference between revisions

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The CLIC2 molecule is box shaped (60×60×35 Å) and consist of a four strand core and two helices on one side. Comparing sequence similarities, the core is supposed to adopt the canonical fold of the glutathione S-transferase (GST) superfamily. This has been confirmed by the crystal structure determination of human CLIC1 at 1.4 Å resolution. Then, by analyzing CLIC genes sequencing, this protein appears to have two potential transmembrane domains that would correspond to helices α1 and α6 in the GST-like structure of the soluble form. Thanks to immunological, electrophysical and proteolysis studies, we can say that membrane form of CLIC proteins cross the lipid bilayer an odd number of times.
The CLIC2 molecule is box shaped (60×60×35 Å) and consist of a four strand core and two helices on one side. Comparing sequence similarities, the core is supposed to adopt the canonical fold of the glutathione S-transferase (GST) superfamily. This has been confirmed by the crystal structure determination of human CLIC1 at 1.4 Å resolution. Then, by analyzing CLIC genes sequencing, this protein appears to have two potential transmembrane domains that would correspond to helices α1 and α6 in the GST-like structure of the soluble form. Thanks to immunological, electrophysical and proteolysis studies, we can say that membrane form of CLIC proteins cross the lipid bilayer an odd number of times.


CLIC2 protein is composed of this GST fold and also with two other domains: an N-terminal domain and a C-terminal domain.
CLIC2 protein is composed of this GST fold and also of two other domains: an N-terminal domain and a C-terminal domain. The <scene name='Sandbox123/N-term_clic2/1'>N-terminal domain</scene>(residues 1-94) has a thioredoxin-like fold made of four-stranded mixed β-sheets and two α-helices running parallel with the sheet of one face (α1 and α3) and one helix (α2) running perpendicular to the sheet on the other face (β α β α β β).  
The N-terminal domain (residues 1-94) has a thioredoxin-like fold made in four-stranded mixed β-sheet and two α-helices running parallel with the sheet of one face (α1 and α3) and one helix (α2) running perpendicular to the sheet on the other face (β α β α β β).
The C-terminal domain (residues 107-245) is exclusively helical composed. It contains a long loop (residues 152-180) between helices 5 and 6, which is a characteristic of the CLIC family wich is called the <scene name='Sandbox123/Foot_loop/1'>foot loop</scene>.  
The C-terminal domain (residues 107-245) is exclusively helical composed. It contains a long loop (residues 152-180) between helices 5 and 6, which is a characteristic of the CLIC family wich is called the <scene name='Sandbox123/Foot_loop/1'>foot loop</scene>.  
Those two domains are linked by an interdomain loop (residues 95–106) rich in proline residues (more than 33% of proline). Actually there are two diproline, Pro70-Pro71 and Pro96-Pro97 in this loop wich is called joint loop. Those diprolines lead to direction changing in the peptide chain. The largest deviations in the N-terminal domain occurs between the residues 55 and 69 that implie helix α2 and its surrounding sequences and also a loop (residues 80-84) that bind the β-strand 4 to helix α3.
Those two domains are linked by an interdomain loop (residues 95–106) rich in proline residues (more than 33% of proline). Actually there are  
<scene name='Sandbox123/Two_diprolines/1'>two diproline</scene>, Pro70-Pro71 and Pro96-Pro97 in this loop wich is called <scene name='Sandbox123/Joint_loop/2'>joint loop</scene>. Those diprolines lead to direction changing in the peptide chain. The largest deviations in the N-terminal domain occurs between the residues 55 and 69 that implie helix α2 and its surrounding sequences and also a loop (residues 80-84) that bind the β-strand 4 to helix α3.
Cristallographic studies gave two forms of CLIC2, on each one we found out that this protein contain a right handed hook conformation. In fact, the long loop between helices 5 and 6 comes out of the surface.
Cristallographic studies gave two forms of CLIC2, on each one we found out that this protein contain a right handed hook conformation. In fact, the long loop between helices 5 and 6 comes out of the surface.


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