1S02

EFFECTS OF ENGINEERED SALT BRIDGES ON THE STABILITY OF SUBTILISIN BPN'

Summary for 1S02

• Entry DOI: 10.2210/pdb1s02/pdb
• Descriptor: SUBTILISIN BPN', CALCIUM ION, SULFATE ION, ... (4 entities in total)
• Functional Keywords: hydrolase (serine proteinase)
• Biological source: Bacillus amyloliquefaciens
• Cellular location: Secreted: P00782
• Total number of polymer chains: 1
• Total formula weight: 27730.71

Authors

Erwin, C.R.,Barnett, B.L.,Oliver, J.D.,Sullivan, J.F. (deposition date: 1991-02-20, release date: 1992-01-15, Last modification date: 2024-02-14)

Primary citation

Erwin, C.R.,Barnett, B.L.,Oliver, J.D.,Sullivan, J.F.
Effects of engineered salt bridges on the stability of subtilisin BPN'.
Protein Eng., 4:87-97, 1990

PubMed Abstract: Variants designed using PROTEUS have been produced in an attempt to engineer stabilizing salt bridges into subtilisin BPN'. All the mutants constructed by site-directed mutagenesis were secreted by Bacillus subtilis, except L75K. Q19E, expressed as a single variant and also in a double variant, Q19E/Q271E, appears to form a stabilizing salt bridge based on X-ray crystal structure determination and differential scanning calorimeter measurements. Although the double mutant was found to be less thermodynamically stable than the wild-type, it did exhibit an autolytic stability about two-fold greater under hydrophobic conditions. Four variants, A98K, S89E, V26R and L235R, were found to be nearly identical to wild-type in thermal stability, indicative of stable structures without evidence of salt bridge formation. Variants Q271E, V51K and T164R led to structures that resulted in varying degrees of thermodynamic and autolytic instability. A computer-modeling analysis of the PROTEUS predictions reveals that the low percentage of salt bridge formation is probably due to an overly simplistic electrostatic model, which does not account for the geometry of the pairwise interactions.

PubMed: 2127106
DOI: 10.1093/protein/4.1.87

Experimental method

X-RAY DIFFRACTION (1.9 Å)