LARGE-SCALE PRODUCTION AND PURIFICATION OF AN ERWINIA-ANANAS ICE NUCLEATION PROTEIN AND EVALUATION OF ITS ICE NUCLEATION ACTIVITY

The ice nucleation-active protein of Erwinia ananas IN-10 (inaA protei n) was over-expressed as inclusion bodies in Escherichia coli in a yie ld of 15.3 mg of inaA protein from 60 mg of bacterial cells on a dry-m atter basis. The inaA protein was purified from the inclusion bodies b y solubilization with detergents to obtain a protein preparation free from sugar and lipid. This preparation had a distinct ice nucleation a ctivity, indicating that the inaA protein per se is able to act as a n ucleus.