Tic40 is one of the essential components of TIC (translocon at the inner envelope of chloroplasts) machinery.
references:
1- Yi-Fen Kao,Yuan-Chao Lou,Yi-Hung Yeh,Chwan-Deng Hsiao,and Chinpan Chen. Solution structure of the C-terminal NP-repeat domain of Tic40, a co-chaperone during protein import into chloroplasts. J Biochem (2012) 152(5): 443-451
2-