ITS2 structure of Sphaeroplea annulina , degrees of conservation and structure alignment. The structure of the internal transcribed spacer 2 of Sphaeroplea annulina shows the common four helices. Helix I is unbranched. Helix I of Scenedesmus obliquus with its branch is underlain in grey. The degree of conservation over the whole alignment is indicated in blue with different degrees of colour saturation. The structural consensus function of 4SALE  returns nucleotides on given percentages. In the upper left corner is the sequence-structure alignment of the conserved distal part of helix III showing a differentiation of the major clades with sequence and/or structure.