6R17

Crystal structure of the SYCE2-TEX12 delta-Ctip 2:2 complex

Summary for 6R17

• Entry DOI: 10.2210/pdb6r17/pdb
• Related: 6HK8
• Descriptor: Synaptonemal complex central element protein 2, Testis-expressed protein 12 (3 entities in total)
• Functional Keywords: synaptonemal complex meiosis recombination coiled-coil self-assembly syce2 tex12 structural protein, structural protein
• Biological source: Homo sapiens (Human); More
• Total number of polymer chains: 4
• Total formula weight: 42255.97

Authors

Dunce, J.M.,Salmon, L.J.,Davies, O.R. (deposition date: 2019-03-13, release date: 2020-09-30, Last modification date: 2024-05-01)

Primary citation

Dunce, J.M.,Salmon, L.J.,Davies, O.R.
Structural basis of meiotic chromosome synaptic elongation through hierarchical fibrous assembly of SYCE2-TEX12.
Nat.Struct.Mol.Biol., 28:681-693, 2021

PubMed Abstract: The 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 μm) depends on its midline α-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 α-fibrous SC backbone that structurally underpins synaptic elongation along meiotic chromosomes.

PubMed: 34373646
DOI: 10.1038/s41594-021-00636-z

Experimental method

X-RAY DIFFRACTION (2.424 Å)