Molecular chaperone (PubMed:15304652, PubMed:21737456, PubMed:24599948). May act as a suppressor of FtsH-mediated thylakoid membrane biogenesis and may enhance photoinhibition (PubMed:15304652). Seems not involved in chloroplastic protein import (PubMed:15304652). Probable component of the TIC-associated stromal import motor involved in inner membrane translocation (PubMed:17376159). Has an ATPase activity, but no ADPase activity (PubMed:21737456). Interacts with transit peptides with a positional preference (PubMed:21737456, PubMed:22545953). Localization of the signal sequence at the N-terminal end of a protein seems mandatory for interaction to take place (PubMed:22545953). ATP + H2O = ADP + H(+) + phosphate Optimum pH is 7.5. Optimum temperature is 55 degrees Celsius. Homodimer and homohexamer (PubMed:21737456). Hexamerization upon addition of ATP (PubMed:21737456). Interacts with CLPT1 (PubMed:25149061). Interacts with CLPS1 (PubMed:23898032). Stably associated with the import machinery (PubMed:21737456). Interacts with CLPF (PubMed:26419670). A number of isoforms are produced. According to EST sequences. Expressed at low levels in roots and inflorescences (PubMed:15659100). Expressed at very low levels in rosette leaves (PubMed:15659100). Expressed in photosynthetic green tissues with high levels in young, developing leaf tissues (PubMed:23898032). By senescence. Not induced by heat stress. No visible phenotype (PubMed:17376159). Clpc1 and clpc2 double mutants are embryo lethal when homozygous (PubMed:17376159). Belongs to the ClpA/ClpB family. ClpC subfamily.