Family 1.A.18 - The Chloroplast Envelope Anion Channel-forming Tic110 Family       

Family ID: 53370

The Tic110 protein of the inner chloroplast envelope membrane is a constituent of the inner membrane protein import apparatus. It has been designated (1) Tic110, (2) IEP110, (3) IAP100 and (4) protein import- related anion channel (PIRAC) by various investigators. It is 996 residues long and exhibits 2 putative 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 (generated by cross linking an in transit precursor protein to the translocation complex). Most of the Tic110 protein is probably in the intermembrane space (between the outer and inner membranes). In this system, transport across the outer and inner membranes probably occurs by two independent processes.

Tic110 appears to be the protein import-related anion-selective channel. The evidence includes complete inactivation of the channel activity by addition of anti Tic110 antibody. The pore size was estimated to be about 6.5Å