EFFECT OF SINGLE AMINO-ACID REPLACEMENT O N T4 PHAGE LYSOZYME STABILITY .1. POINT MUTATION ASN101-]ASP

The amino acid replacement Asn101-->Asp in the T4 phage lysozyme was o btained by site-directed mutagenesis and the plasmid mutant protein ex pression was constructed. Though the mutant protein circular dichroism (CD) spectrum is virtually unchanged as compared with the wild type p rotein and the enzymatic activity is 90% of that of the wild type prot ein, the stability of this mutant to urea-induced unfolding decreasees and two stages in the denaturation process are observed.