English: (A) Chloroplast ribosome (green). Compared to (B) bacterial ribosome cryoEM structure (yellow; [29]). Left and right views are related by 180° rotation as indicated. At left is a classic side view of the ribosome with the large subunit on the left and the small subunit on the right; right view shows the small subunit on the left and the large subunit on the right. Common ribosome landmarks as well as chloroplast-unique structures are clearly defined on the chloroplast ribosome, and have been labeled. bk, beak; CP, central protuberance; cuα, cuβ, cuγ, and CUλ, chloroplast-unique structures; h, head; L1, L1 arm; pt, platform; sh, shoulder; sp, spur; ST, stalk.(description taken from PLOS article)