1lyn
CRYSTAL STRUCTURE AND SUBUNIT DYNAMICS OF THE LYSIN DIMER: EGG ENVELOPES DISSOCIATE DIMERS, THE MONOMER IS THE ACTIVE SPECIES
OverviewOverview
Lysin is a 16-kD acrosomal protein used by abalone spermatozoa to create a hole in the egg vitelline envelope (VE) by a nonenzymatic mechanism. The crystal structure of the lysin monomer is known at 1.9 A resolution. The surface of the molecule reveals two tracks of basic residues running the length of one surface of the molecule and a patch of solvent-exposed hydrophobic residues on the opposite surface. Here we report that lysin dimerizes via interaction of the hydrophobic patches of monomers. Triton X-100 dissociates the dimer. The crystal structure of the dimer is described at 2.75 A resolution. Fluorescence energy transfer experiments show that the dimer has an approximate KD of 1 microM and that monomers exchange rapidly between dimers. Addition of isolated egg VE dissociates dimers, implicating monomers as the active species in the dissolution reaction. This work represents the first step in the elucidation of the mechanism by which lysin enables abalone spermatozoa to create a hole in the egg envelope during fertilization.
About this StructureAbout this Structure
1LYN is a Single protein structure of sequence from Haliotis rufescens. Full crystallographic information is available from OCA.
ReferenceReference
Crystal structure and subunit dynamics of the abalone sperm lysin dimer: egg envelopes dissociate dimers, the monomer is the active species., Shaw A, Fortes PA, Stout CD, Vacquier VD, J Cell Biol. 1995 Sep;130(5):1117-25. PMID:7657696 Page seeded by OCA on Sat May 3 00:25:47 2008