Catalyzes the conversion of precorrin-2 into siroheme. This reaction consist of the NAD-dependent oxidation of precorrin-2 into sirohydrochlorin and its subsequent ferrochelation into siroheme. NAD(+) + precorrin-2 = 2 H(+) + NADH + sirohydrochlorin 2 H(+) + siroheme = Fe(2+) + sirohydrochlorin Porphyrin-containing compound metabolism; siroheme biosynthesis; siroheme from sirohydrochlorin: step 1/1. Porphyrin-containing compound metabolism; siroheme biosynthesis; sirohydrochlorin from precorrin-2: step 1/1. Homodimer. Belongs to the precorrin-2 dehydrogenase / sirohydrochlorin ferrochelatase family. MET8 subfamily.