Figure 2.

The structural features of AtLon1 protease and the locations of the identified mutations. (A) Schematic representation of AtLon1 protease outlining the domain structures with important consensus sequences in lon1 mutant alleles. Numbers in parentheses represent amino acid residues defining the conserved domains. (B) Multiple sequence alignment reveals that the SSD is the most variable domain between evolutionary diverse Lon accessions. Box encompasses the amino acid residues of sensor-2 motif. In contrast to the strong lon1-1 allele (asterisk), the weak lon1-2 mutant allele (inverted triangle) bears part of the SSD domain.