This family includes proteins that have two copies of a cysteine rich motif as follows: C-X-C-X4-C-X3-YC-X-C-X6-C-X3-C-X-C-X2-C. The family includes Tesmin Swiss:Q9Y4I5 [1] and TSO1 Swiss:Q9LE32 [2]. This family is called a CXC domain in [2].

1: A novel testis-specific metallothionein-like protein, tesmin, is an early marker of male germ cell differentiation. Sugihara T, Wadhwa R, Kaul SC, Mitsui Y; Genomics 1999;57:130-136. PMID:10191092

2: TSO1 is a novel protein that modulates cytokinesis and cell expansion in Arabidopsis. Hauser BA, He JQ, Park SO, Gasser CS; Development 2000;127:2219-2226. PMID:10769245