MOLECULAR-ORGANIZATION OF THE ICE NUCLEATION PROTEIN INAV FROM PSEUDOMONAS-SYRINGAE

A new ice nucleation gene from Pseudomonas syringae was isolated and o verexpressed as a fully active protein in Escherichia coli in order to gain experimental data about the structure of ice nucleation proteins , No evidence of a signal sequence or secondary glycosylation was foun d, Differences in the extent of aggregation were shown to modulate the ice nucleation activity. The circular dichroism spectrum of the purif ied protein indicated the presence of beta-sheet structure, This findi ng supports a recently proposed hypothetical model for the structure o f ice nucleation proteins, which provides a plausible explanation for their aggregation tendency. (C) 1997 Federation of European Biochemica l Societies.