Twin-arginine-dependent translocation of folded proteins 

 -  Phil. Trans. R. Soc., 367(1592), p.1029-1046, 2012 .
<br/><br/> Twin-arginine translocation (Tat)denotes a protein transport pathway in bacteria, archaea and plant chloroplasts, which is specific for precursor proteins harbouring a characteristic twin-arginine pair in their signal sequences. Many Tat substrates receive cofactors and fold prior to translocation. For a subset of them, proofreading chaperones coordinate maturation and membrane-targeting. Tat translocases comprise two kinds of membrane proteins, a hexahelical TatC-type protein and one or two members of the single-spanning TatA protein family, called TatA and TatB. TatC- and TatAtype proteins form homo- and hetero-oligomeric complexes. The subunits of TatABC translocases are predominantly recovered from two separate complexes, a TatBC complex that might contain some TatA, and a homomeric TatA complex. TatB and TatC coordinately recognize twin-arginine signal peptides and accommodate them in membrane-embedded binding pockets. Advanced binding of the signal sequence to the Tat translocase requires the proton-motive force (PMF)across the membranes and might involve a first recruitment of TatA. When targeted in this manner, folded twin-arginine precursors induce homo-oligomerization of TatB and TatA. Ultimately, this leads to the formation of a transmembrane protein conduit that possibly consists of a pore-like TatA structure. The translocation step again is dependent on the PMF. 
<br/><br/><label>Subjects--Topical Terms: </label><br/>TATA PORE<br/>TATBC RECEPTOR<br/>TATA-TYPE PROTEIN<br/>TATC-TYPE PROTEIN<br/>PROOFREADING CHAPERONES<br/>TWIN-ARGININE TRANSLOCATION (TAT)