The Chloroplast Envelope Anion Channel-forming Tic110 (Tic110) Family
TC#1.A.18
consists of proteins of the inner chloroplast envelope membrane. This family consists of the inner membrane protein import apparatus, and appears to be a protein import-related anion-selective channel. It has also been designated (1) IEP110, (2) IAP100 and (3) protein import-related anion

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(PIRAC).

Location

Most of the Tic110 protein is probably in the

intermembrane space The intermembrane space (IMS) is the space occurring between or involving two or more membranes. In cell biology, it is most commonly described as the region between the Inner mitochondrial membrane, inner membrane and the Outer mitochondrial memb ...

. Transport across the outer and inner membranes probably occurs by two independent processes.

Structure

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'' Tic 110 is 996 amino acyl residues long and exhibits 2 putative transmembrane segments (TMSs) near its N-terminus at positions 74-92 and 101-120. Biochemical analyses suggest that this protein is part of a 600 kDa complex. Tic110 has two proposed functions with naturally exclusive structures; a protein-conducting channel with 6 TMSs, and a scaffold with 2 N-terminal TMSs followed by a large soluble domain for binding transit peptides and other stromal translocon components. The C-terminal half of Tic110 possesses a rod-shaped helix-repeat structure that is too flattened and elongated to be a channel. The structure is most similar to the HEAT-repeat motif that functions as scaffolds for protein-protein interactions. The pore size was estimated to be about 6.5 Å.

Transport Reaction

The transport reactions across the chloroplast inner membrane catalyzed by Tic110 are: : (1) anions (out) ⇌ anions (in) : (2) proteins (out) → proteins (in)

References

{{CCBYSASource, sourcepath=http://www.tcdb.org/search/result.php?tc=1.a.18, sourcearticle=1.A.18 The Chloroplast Envelope Anion Channel-forming Tic110 (Tic110) Family, revision=699838558 Protein families Membrane proteins Transmembrane proteins Transmembrane transporters Transport proteins Integral membrane proteins