TY - JOUR TI - Unconventional conservation reveals structure-function relationships in the synaptonemal complex AU - Kursel, Lisa E AU - Cope, Henry D AU - Rog, Ofer A2 - Levine, Mia T A2 - Tyler, Jessica K VL - 10 PY - 2021 DA - 2021/11/17 SP - e72061 C1 - eLife 2021;10:e72061 DO - 10.7554/eLife.72061 UR - https://doi.org/10.7554/eLife.72061 AB - Functional requirements constrain protein evolution, commonly manifesting in a conserved amino acid sequence. Here, we extend this idea to secondary structural features by tracking their conservation in essential meiotic proteins with highly diverged sequences. The synaptonemal complex (SC) is a ~100-nm-wide ladder-like meiotic structure present in all eukaryotic clades, where it aligns parental chromosomes and regulates exchanges between them. Despite the conserved ultrastructure and functions of the SC, SC proteins are highly divergent within Caenorhabditis. However, SC proteins have highly conserved length and coiled-coil domain structure. We found the same unconventional conservation signature in Drosophila and mammals, and used it to identify a novel SC protein in Pristionchus pacificus, Ppa-SYP-1. Our work suggests that coiled-coils play wide-ranging roles in the structure and function of the SC, and more broadly, that expanding sequence analysis beyond measures of per-site similarity can enhance our understanding of protein evolution and function. KW - P. pacificus KW - meiosis KW - synaptonemal complex KW - coiled-coil KW - indel KW - evolution JF - eLife SN - 2050-084X PB - eLife Sciences Publications, Ltd ER -