title: 2.6 A resolution crystal structure of helices of the motile major sperm protein (MSP) of Caenorhabditis elegans.
abstract: The amoeboid locomotion of nematode sperm is mediated by the assembly dynamics of the major sperm protein (MSP). MSP forms fibrous networks based on a hierarchy of macromolecular assemblies: helical subfilaments are built from MSP dimers; filaments are formed from two subfilaments coiling round one another; and filaments themselves supercoil to produce bundles. To provide a structural context for understanding the role of these macromolecular assemblies in cell locomotion, we have determined the 2.6 A resolution structure of crystals of Caenorhabditis elegans MSP that are constructed from helices of MSP chains that are analogous to the subfilaments from which filaments are constructed. Comparison with the crystal structures of dimers and helical assemblies of Ascaris suum MSP has identified five conserved interaction interfaces that suggest how subfilaments interact in filaments and how filaments can form bundles. The interfaces frequently involve the loop containing residues 78-85, which is divergent between MSP homologues, and the loop containing residues 98-103, which is highly conserved.
authors.affiliation: MRC Laboratory of Molecular Biology, Hills Road, Cambridge CB2 2QH, UK.
authors.forename: Anne M E
authors.initials: AM
authors.lastname: Baker
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Roberts
authors.forename: Murray
authors.initials: M
authors.lastname: Stewart
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D017165:Ascaris suum / Q000737:chemistry; D001665:Binding Sites; D017173:Caenorhabditis elegans / Q000737:chemistry*; D029742:Caenorhabditis elegans Proteins / Q000737:chemistry / Q000378:metabolism / Q000648:ultrastructure; D018360:Crystallography, X-Ray; D015801:Helminth Proteins / Q000737:chemistry* / Q000378:metabolism / Q000648:ultrastructure; D006860:Hydrogen Bonding; D008854:Microscopy, Electron; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011487:Protein Conformation; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism
chemical_list: D029742:Caenorhabditis elegans Proteins; D015801:Helminth Proteins; D011994:Recombinant Proteins; C050602:major sperm protein, nematode