This domain contains conserved cysteine and histidine residues [1]. It resembles zinc fingers, and binds to zinc [2]. This domain functions as an RNA-binding domain [2].

1: ACCUMULATION OF PHOTOSYSTEM ONE1, a member of a novel gene family, is required for accumulation of [4Fe-4S] cluster-containing chloroplast complexes and antenna proteins. Amann K, Lezhneva L, Wanner G, Herrmann RG, Meurer J; Plant Cell. 2004;16:3084-3097. PMID:15494558

2: APO1 Promotes the Splicing of Chloroplast Group II Introns and Harbors a Plant-Specific Zinc-Dependent RNA Binding Domain. Watkins KP, Rojas M, Friso G, van Wijk KJ, Meurer J, Barkan A; Plant Cell. 2011;0:0-0. PMID:21421812