Fig. 2

Sequence alignment of the invertebrate SINA subfamily reveals its invariant amino acid residues, and the four conserved structural motifs. Sequence comparison of SINA proteins from 20 representative invertebrate species (#1-#20) is shown. a Overview of the entire alignment produced by the 20 invertebrate SINA sequences. Four key functional domains are marked in four distinct colors: RING domain (orange), SZF domain (blue), SBS (red), and DIMER domain (green). b Schematic illustration of amino acid conservation within the 4 domains of the SINA sequences is shown. Amino acid identity is shown as white letters in a black box, amino acid similarity is shown as white letters in a grey box, and amino acid divergence is shown as black letters in a white box. The asterisks located below the RING domain alignment indicate unanimous conservation of the cysteine/histidine zinc-binding residues. c The percentages of amino acid conservation in each distinct domain and the entire SINA sequence between Branchiostoma floridae and each of the representative invertebrate species are shown. The diagram of the domain architecture was based on B. floridae SINA