1gak Citations

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

Biochemistry 40 5407-13 (2001)
Cited: 10 times
EuropePMC logo PMID: 11331004


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.

Reviews citing this publication (5)

  1. From molecules to mating: Rapid evolution and biochemical studies of reproductive proteins. Wilburn DB, Swanson WJ. J Proteomics 135 12-25 (2016)
  2. Sperm-egg interaction. Evans JP. Annu. Rev. Physiol. 74 477-502 (2012)
  3. The quest for the sea urchin egg receptor for sperm. Vacquier VD. Biochem. Biophys. Res. Commun. 425 583-587 (2012)
  4. Selection in the rapid evolution of gamete recognition proteins in marine invertebrates. Vacquier VD, Swanson WJ. Cold Spring Harb Perspect Biol 3 a002931 (2011)
  5. Gamete interaction: is it species-specific? Vieira A, Miller DJ. Mol. Reprod. Dev. 73 1422-1429 (2006)

Articles citing this publication (5)

  1. MMTSB Tool Set: enhanced sampling and multiscale modeling methods for applications in structural biology. Feig M, Karanicolas J, Brooks CL. J. Mol. Graph. Model. 22 377-395 (2004)
  2. Is HAP2-GCS1 an ancestral gamete fusogen? Wong JL, Johnson MA. Trends Cell Biol. 20 134-141 (2010)
  3. ZP domain proteins in the abalone egg coat include a paralog of VERL under positive selection that binds lysin and 18-kDa sperm proteins. Aagaard JE, Vacquier VD, MacCoss MJ, Swanson WJ. Mol. Biol. Evol. 27 193-203 (2010)
  4. Sperm Lysozyme-Like Protein 1 (SLLP1), an intra-acrosomal oolemmal-binding sperm protein, reveals filamentous organization in protein crystal form. Zheng H, Mandal A, Shumilin IA, Chordia MD, Panneerdoss S, Herr JC, Minor W. Andrology 3 756-771 (2015)
  5. Indirect sexual selection drives rapid sperm protein evolution in abalone. Wilburn DB, Tuttle LM, Klevit RE, Swanson WJ. Elife 8 (2019)