Table 1.

Percentages of amino acid identity and similarity of the structural domains between AtLon1^a and the arabidopsis AtLon2 and AtLon4 or the non-plant Lon homologs^b

	% Amino acid (identity/similarity)
	AAA+ domain (484–642aa)	SSD-domain (649–810aa)
AtLon4	91/94	63/74
PIM1	75/87	38/64
NP_004874	79/91	35/45
AtLon2	61/80	20/39
EcLon	61/77	21/34

^aCoordinates of the AtLon1 domains in parentheses were defined by the comparative analysis with EcLon protease primary structure although there is no absolute definition and the domain boundaries are frequently subjected to revisions.

^bThe Lon protein accessions are AtLon1 (At5g26860), AtLon2 (At5g47040) and AtLon4 (At3g05790) from Arabidopsis thaliana, the Homo sapiens Lon1 (NP_004784), PIM1 (P36775) from Saccharomyces cerevisiae and EcLon (AAC36871) from Escherichia coli.