A new metabolic pathway for <i>sym</i>-homospermidine synthesis in an extreme thermophile, <i>Thermus thermophilus.</i>

In an extreme thermophile, Thermus thermophilus, sym-homospermidine is synthesized by the actions of two enzymes. The first enzyme coded by dhs gene (annotated to be deoxyhypusine synthase gene) catalyzes synthesis of an intermediate, supposed to be 1,9-bis(guanidino)-5-aza-nonane (=N¹, N¹¹-bis(amidino)-sym-homospermidine), from two molecules of agmatine in the presence of NAD. The second enzyme (aminopropylagmatinase) coded by speB gene catalyzes hydrolysis of the intermediate compound to sym-homospermidine releasing two molecules of urea.