1GAK

CRYSTAL STRUCTURE OF GREEN ABALONE SP18


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.85 Å
  • R-Value Free: 0.247 
  • R-Value Work: 0.227 

wwPDB Validation   3D Report Full Report


This is version 1.2 of the entry. See complete history


Literature

The crystal structure of a fusagenic sperm protein reveals extreme surface properties.

Kresge, N.Vacquier, V.D.Stout, C.D.

(2001) Biochemistry 40: 5407-5413

  • DOI: 10.1021/bi002779v
  • Primary Citation of Related Structures:  
    1GAK

  • PubMed Abstract: 
  • Sp18 is an 18 kDa protein that is released from abalone sperm during the acrosome reaction. It coats the acrosomal process where it is thought to mediate fusion between sperm and egg cell membranes. Sp18 is evolutionarily related to lysin, a 16 kDa abalone sperm protein that dissolves the vitelline envelope surrounding the egg ...

    Sp18 is an 18 kDa protein that is released from abalone sperm during the acrosome reaction. It coats the acrosomal process where it is thought to mediate fusion between sperm and egg cell membranes. Sp18 is evolutionarily related to lysin, a 16 kDa abalone sperm protein that dissolves the vitelline envelope surrounding the egg. The two proteins were generated by gene duplication followed by rapid divergence by positive selection. Here, we present the crystal structure of green abalone sp18 resolved to 1.86 A. Sp18 is composed of a bundle of five alpha-helices with surface clusters of basic and hydrophobic residues, giving it a large dipole moment and making it extremely amphipathic. The large clusters of hydrophobic surface residues and domains of high positive electrostatic surface charge explain sp18's ability as a potent fusagen of liposomes. The overall fold of sp18 is similar to that of green abalone lysin; however, the surface features of the proteins are quite different, accounting for their different roles in fertilization. This is the first crystal structure of a protein implicated in sperm-egg fusion during animal fertilization.


    Organizational Affiliation

    Department of Molecular Biology, The Scripps Research Institute, La Jolla, California 92037-1093, USA.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
FERTILIZATION PROTEINA141Haliotis fulgensMutation(s): 0 
Find proteins for Q25063 (Haliotis fulgens)
Explore Q25063 
Go to UniProtKB:  Q25063
Protein Feature View
Expand
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.85 Å
  • R-Value Free: 0.247 
  • R-Value Work: 0.227 
  • Space Group: P 65
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 68.76α = 90
b = 68.76β = 90
c = 67.71γ = 120
Software Package:
Software NamePurpose
MOSFLMdata reduction
SCALAdata scaling
SHARPphasing
CNSrefinement
CCP4data scaling

Structure Validation

View Full Validation Report



Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2000-12-13
    Type: Initial release
  • Version 1.1: 2008-04-27
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance