Chaperone, tailless complex polypeptide 1 <p>Protein folding is thought to be the sole result of properties inherent in polypeptide primary sequences. Sometimes, however, additional proteins are required to mediate correct folding and subsequent oligomer assembly [<cite idref="PUB00004022"/>]. These `helpers', or chaperones, bind to specific protein surfaces, preventing incorrect folding and formation of non-functional structures [<cite idref="PUB00001821"/>].</p><p>The tailless complex polypeptide 1 (TCP-1) is a highly structurally conserved molecular chaperone located in the cytosol [<cite idref="PUB00044610"/>]. The protein has also been shown to bind to Golgi membranes and to microtubules, this latter property suggesting a role in mitotic spindle formation in dividing cells (especially in sperm, where it is highly abundant) [<cite idref="PUB00004112"/>]. TCP-1 forms a double ring structure, similar to the 10kDa and 60kDa chaperonins, with 6-8 subunits per ring. The amino acid sequence is significantly similar to the 60kDa chaperonin, and to TF55, a chaperone from the archaebacterium <taxon tax_id="2286">Sulfolobus shibatae</taxon> [<cite idref="PUB00004112"/>].</p>