Characterization of a family of ice-active proteins from the Ryegrass, Lolium perenne

Cryobiology. 2008 Dec;57(3):263-8. doi: 10.1016/j.cryobiol.2008.09.005. Epub 2008 Sep 19.


Five genes coding for ice-active proteins were identified from an expressed sequence tag database of Lolium perenne cDNA libraries. Each of the five genes were characterized by the presence of an N-terminal signal peptide, a region enriched in hydrophilic amino acids and a leucine-rich region in four of the five genes that is homologous with the receptor domain of receptor-like protein kinases of plants. The C-terminal region of all five genes contains sequence homologous with Lolium and Triticum ice-active proteins. Of the four ice-active proteins (IAP1, IAP2, IAP3 and IAP5) cloned, three could be expressed in Escherichia coli and recovered in a functional form in order to study their ice activity. All three ice-active proteins had recrystallization inhibition activity but showed no detectable antifreeze or ice nucleation activity at the concentration tested. IAP2 and IAP5 formed distinct hexagonal-shaped crystals in the nanolitre osmometer as compared to the weakly hexagonal crystals produced by IAP3.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antifreeze Proteins / metabolism
  • Crystallization
  • Freezing
  • Heating
  • Ice
  • Lolium / genetics*
  • Lolium / metabolism*
  • Osmolar Concentration
  • Plant Proteins / genetics*
  • Plant Proteins / metabolism*
  • Recombinant Proteins / metabolism
  • Sequence Homology, Amino Acid


  • Antifreeze Proteins
  • Ice
  • Plant Proteins
  • Recombinant Proteins