Triple point mutation Asp10-->His, Asn101-->Asp, Arg148-->Ser in T4 phage lysozyme leads to the molten globule.

The triple amino acid replacement (Asp10-->His, Asn101-->Asp, Arg148-->Ser) in T4 phage lysozyme was carried out by site-directed mutagenesis. At acid pH (2.7) the mutant is in a conformational state with the properties of the molten globule: (i) the mutant protein molecule is essentially compact; (ii) its CD spectrum in the near UV region is drastically reduced in intensity as compared with the wild type protein spectrum; (iii) the CD spectrum in the far UV region indicates the presence of pronounced secondary structure in the mutant; (iv) unlike the wild type protein the mutant protein can bind the hydrophobic fluorescent probe, ANS.