This family contains several uncharacterised bacterial proteins. These proteins are found in nitrogen fixation operons so are likely to play some role in this process. They consist of two alpha helices which are joined by a four residue linker. The helices form an antiparallel bundle and cross towards their termini. They are likely to form a rod-like dimer [1]. They have structural similarity to the regulatory protein Rop, Pfam:PF01815.

1: Structural characterization of the protein cce_0567 from Cyanothece 51142, a metalloprotein associated with nitrogen fixation in the DUF683 family. Buchko GW, Robinson H, Addlagatta A; Biochim Biophys Acta. 2009;1794:627-633. PMID:19336042