An example of a protected page: a tutorial on Ramachandran plots. This image shows a section of a page containing a tutorial on Ramachandran plots. The green links in this section allow the user reading the page to compare the Ramachandran plots of three proteins with dissimilar structures by first viewing the three-dimensional structure of a particular protein and then viewing its Ramachandran plot. The plot displayed in the Jmol applet in the figure is that of acetylcholinesterase from PDB file 1eve. Points on the plot representing residues from α-helices are drawn in red, points representing residues from β-sheets are yellow, and points representing the other residues are in white. This page was authored by Professor Karl Oberholser, Department of Chemistry and Biochemistry, Messiah College, PA, USA. The page is titled "User:Karl_Oberholser/Ramachandran_Plots" (see ). "User:Karl_Oberholser" is Karl Oberholser's userpage, and this Ramachandran Plot page is a subpage of his userpage. All userpages and subpages thereof are editable only by their eponymous users. Since this Ramachandran plot page is a subpage of a userpage, it is editable only by Karl Oberholser, and is referred to as a protected page. He can count on this protected page in the wiki being unchanged, and use it as a three-dimensional "lecture slide". Since all user-added content in Proteopedia is released under the GNU FDL, other users may copy content from this page and add it to a publicly editable page, or another protected page, in Proteopedia with proper attribution to its author.