28953
PfRRF1 carries a large 108 - amino - acid insertion in the functionally critical hinge region between the head and tail domains of the protein , yet complemented Escherichia coli RRF in the LJ14frr ( ts ) mutant and disassembled surrogate E . coli 70S ribosomes in the presence of apicoplast - targeted EF - G .
 amino - acid
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 amino - acid