Investigations of staphylococcal nuclease variants that differ by single amino acid replacements: pH and temperature dependence of /sup 1/H NMR spectra

Journal Article · Thu May 01 00:00:00 EDT 1986 · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)

OSTI ID:6992446

Alexandrescu, A T; Ulrich, E L; Grissom, C B; Mills, D A; Shortle, D; Markley, J L

Comparisons have been made between the nuclease (SNase) from S. aureus, cloned and overproduced in E. coli, with protein variants that differ from it by single residue replacements: H46Y, H124R, and F76V. /sup 1/H NMR spectra obtained at 25/sup 0/C of H46Y and H124R are quite similar to that of SNase except for resonances from the side chain at the modified sites. The results confirm earlier histidine assignments. The pK/sub a/ values of those histidine residues conserved in all three proteins are similar. By contrast, spectra of SNase and F76V show numerous differences that cannot be attributed to the change in residue 76. This indicates that the amino acid replacement leads to a change in the conformation of the protein. The thermal denaturation temperature of F76V is 42/sup 0/ as compared to 54/sup 0/C for SNase. The differences in the spectra of F76V and SNase at 80/sup 0/C can be explained simply by the substituted side chain at position 76.

• Research Organization: Univ. of Wisconsin, Madison
• OSTI ID: 6992446
• Report Number(s): CONF-8606151-
• Journal Information: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Vol. 45:6; Conference: 76. annual meeting of the Federation of American Society for Experimental Biology, Washington, DC, USA, 8 Jun 1986
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
62 RADIOLOGY AND NUCLEAR MEDICINE
NUCLEASES
PROTEIN STRUCTURE
AMINO ACIDS
MOLECULAR STRUCTURE
NMR SPECTRA
NUCLEAR MAGNETIC RESONANCE
STAPHYLOCOCCUS
BACTERIA
CARBOXYLIC ACIDS
ENZYMES
ESTERASES
HYDROLASES
MAGNETIC RESONANCE
MICROORGANISMS
ORGANIC ACIDS
ORGANIC COMPOUNDS
PHOSPHODIESTERASES
RESONANCE
SPECTRA
550201* - Biochemistry- Tracer Techniques
550600 - Medicine