6yqf | pdb_00006yqf
Crystal structure of the SYCE2-TEX12 delta-Ctip complex in a 4:4 assembly
Structural highlights
FunctionSYCE2_HUMAN Major component of the transverse central element of synaptonemal complexes (SCS), formed between homologous chromosomes during meiotic prophase. Requires SYCP1 in order to be incorporated into the central element. May have a role in the synaptonemal complex assembly, stabilization and recombination (By similarity).[UniProtKB:Q505B8] Publication Abstract from PubMedThe synaptonemal complex (SC) is a supramolecular protein assembly that mediates synapsis between homologous chromosomes during meiosis. SC elongation along the chromosome length (up to 24 mum) depends on its midline alpha-fibrous component SYCE2-TEX12. Here, we report X-ray crystal structures of human SYCE2-TEX12 as an individual building block and on assembly within a fibrous lattice. We combine these structures with mutagenesis, biophysics and electron microscopy to reveal the hierarchical mechanism of SYCE2-TEX12 fiber assembly. SYCE2-TEX12's building blocks are 2:2 coiled coils that dimerize into 4:4 hetero-oligomers and interact end-to-end and laterally to form 10-nm fibers that intertwine within 40-nm bundled micrometer-long fibers that define the SC's midline structure. This assembly mechanism bears striking resemblance with intermediate filament proteins vimentin, lamin and keratin. Thus, SYCE2-TEX12 exhibits behavior typical of cytoskeletal proteins to provide an alpha-fibrous SC backbone that structurally underpins synaptic elongation along meiotic chromosomes. Structural basis of meiotic chromosome synaptic elongation through hierarchical fibrous assembly of SYCE2-TEX12.,Dunce JM, Salmon LJ, Davies OR Nat Struct Mol Biol. 2021 Aug;28(8):681-693. doi: 10.1038/s41594-021-00636-z. , Epub 2021 Aug 9. PMID:34373646[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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