An ice-binding protein from an Arctic grass, Leymus mollis [version 1; peer review: 2 approved]

Abstract

Several cold-hardy grasses have been shown to have ice-binding proteins (IBPs) that protect against freeze-thaw injury. Here, we looked for IBP activity in an Alaskan coastal grass that had not previously been examined, Leymus mollis (Pooidae). Rhizome tissue had strong ice-structuring and ice recrystallization inhibiting (IRI) activities, indicating the probable presence of IBPs. The gene sequence of an IBP was obtained. The sequence encoded a 118-amino acid IRI domain that contained eight repeats. A 3D structure of the IRI domain was predicted from the structure of the IRI domain of the perennial ryegrass Lolium perenne. The predicted structure appeared to have the same eight beta-roll coils found in the L. perenne IBP.