FIG 2.

A quartet of spore resistance-associated molecules. (A) Pyridine-2,6-dicarboxylic acid (DPA), which would be charged and chelated with Ca²⁺ ions in the spore core; (B) thyminyl-thymine adduct, often referred to as spore photoproduct (SP); (C) SASP-DNA complex (DNA, blue and orange) (Protein Data Bank [PDB] 2z3x); (D) SP lyase with S-adenosyl-l-methionine cofactor (blue) bound at the iron-sulfur cluster (yellow and orange) (PDB 4fhc).