Stability studies of amino acid substitutions at tyrosine 27 of the staphylococcal nuclease beta-barrel.
In order to help determine the extent to which side chain interactions within the staphylococcal nuclease beta-barrel affect its global stability, a full set of point mutants was generated for residue 27. Intrinsic tryptophan fluorescence was monitored during solvent denaturation with guanidine hydrochloride (GuHCl) and was used to calculate DeltaGH2O unfolding and m values for each mutant. In the wild type protein, residue 27 is a tyrosine which is at the first position of a type I' beta-turn, and which participates in both hydrophobic interactions and side chain to side chain hydrogen bonding. The hydrophobicity of the mutant residue was found to be the dominant factor in determining global protein stability within this series of nuclease mutants.
Bhat
M G
MG
Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06511, USA.
Ganley
L M
LM
Ledman
D W
DW
Goodman
M A
MA
Fox
R O
RO
D000595:Amino Acid Sequence; D004795:Enzyme Stability / Q000235:genetics; D013058:Mass Spectrometry; D008836:Micrococcal Nuclease / Q000737:chemistry* / Q000235:genetics*; D016297:Mutagenesis, Site-Directed; D011489:Protein Denaturation / Q000235:genetics; D017433:Protein Structure, Secondary; D013050:Spectrometry, Fluorescence; D014364:Tryptophan / Q000235:genetics; D014443:Tyrosine / Q000235:genetics*
D014443:Tyrosine; D014364:Tryptophan; D008836:Micrococcal Nuclease