Purification and Partial Amino Acid Sequence of the Major 70,000-Dalton Heat Shock Protein in Neurospora crassa

Fracella, F., Mohsenzadeh, S., and Rensing, L. 1993. Purification and partial amino acid sequence of the major 70,000-Dalton heat shock protein in Neurospora crassa. Experimental Mycology , 17, 362-367. The major heat shock protein of 70 kDa (hsp70) from heat-shocked mycelial extracts of Neurospora crassa was purified to near homogeneity employing DEAE anion-exchange chromatography followed by affinity chromatography on ATP-agarose. The isolated hsp70 migrates as a single band on one-dimensional sodium dodecyl sulfate polyacrylamide gels (SDS-PAGE), with a molecular mass of ∼69 kDa. On two-dimensional gels it is resolved into two polypeptides with isoelectric points in the acidic range of ∼pH 5.2. The first 53 amino terminal amino acids of the major protein were sequenced and compared with hsp70 of other species. The amino acids aspartic acid, arginine, and phenylalanine occur at positions 27, 28, and 44 (from the methionine terminus) in contrast to the main consensus sequence. These three differing amino acids are shared by yeast, and, in addition, the first two by Arabidopsis, petunia, and maize.