title: Structure of sperm-specific protein SSP-19 from Caenorhabditis elegans.
abstract: Structural data are reported for SSP-19, a sperm-specific protein (SSP) family member from Caenorhabditis elegans. The SSP family [also known as the major sperm protein-like (MSP-like) family] contains proteins with only 107-109 amino acids, compared with 127 amino acids in the major sperm protein (MSP) family. MSP, the most abundant protein in nematode sperm, forms a dynamic actin-like cytoskeleton that provides the framework for the nematode sperm motility. In vivo, MSP dimers polymerize to form filaments that are constructed from two helical strands, which assemble into larger macromolecular structures. Little is known about the SSP family and a similar function is inferred from sequence and structural homology [Pfam (Protein Families Database of Alignments and HMMs) and SCOP (Structural Classification of Proteins) classification]. Despite the overall structural homology, the monomer-monomer interactions in SSP-19 are strikingly different from the interactions in the two MSP canonic domains described previously.
authors.affiliation: Southeast Collaboratory for Structural Genomics, Center for Biophysical Sciences and Engineering, University of Alabama at Birmingham, Birmingham, Alabama, USA.
authors.forename: Norbert
authors.initials: N
authors.lastname: Schormann
authors.forename: Jindrich
authors.initials: J
authors.lastname: Symersky
authors.forename: Ming
authors.initials: M
authors.lastname: Luo
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D017173:Caenorhabditis elegans; D029742:Caenorhabditis elegans Proteins / Q000737:chemistry*; D003001:Cloning, Molecular; D018360:Crystallography, X-Ray; D019281:Dimerization; D008297:Male; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D029589:Seminal Plasma Proteins / Q000737:chemistry*; D017386:Sequence Homology, Amino Acid; D013094:Spermatozoa / Q000378:metabolism*
chemical_list: D029742:Caenorhabditis elegans Proteins; D010455:Peptides; C498063:SSP-19 protein, C elegans; D029589:Seminal Plasma Proteins