The longest IMRs coincide with key protein functional motifs. Figures 2A and 2B [NCBI:1L6N ] illustrate the two longest mIMRs in the Gag polyprotein – #1-gag in matrix and #2-gag in capsid. These mIMRs translate the MA H5 and CA H7 helices which (in the illustrated structure) are approximately parallel to each other at a pitch of about 45°. Both are essential to the structure and function of each protein. Figure 2C illustrates the largest rdIMRs in matrix and Figure 2D the largest rdIMRs in capsid, that do not coincide with mIMRs.