Single mutation at the intersubunit interface confers extra efficiency to Cu,Zn superoxide dismutase.

Journal article

The Val28-->Gly single mutant at the subunit interface of Cu,Zn superoxide dismutase from Photobacterium leiognathi displays a k(cat)/K(M) value of 1.7x10(10) M(-1) s(-1), twice that of the native enzyme. Analysis of the three-dimensional structure indicates that the active site Cu,Zn center is not perturbed, slight structural deviations being only localized in proximity of the mutation site. The enzyme-substrate association rate, calculated by Brownian dynamics simulation, is identical for both enzymes, indicating that the higher catalytic efficiency of the Val28-->Gly mutant is not due to a more favorable electrostatic potential distribution. This result demonstrates the occurrence of an intramolecular communication between the mutation site and the catalytic center, about 18 A away and indicates a new strategy to encode extra efficiency within other members of this enzymatic family.

Authors: Stroppolo, M; Pesce, A; Falconi, M; O'Neill, P; Bolognesi, M

• Publication status: Published
• Journal: FEBS letters
• Volume: 483
• Issue: 1
• Pages: 17-20
• Publication date: 2000-10-01
• DOI: 10.1016/s0014-5793(00)01967-0
• EISSN: 1873-3468
• ISSN: 0014-5793
• Language: English
• Keywords: Amino Acid Substitution; Hydrogen-Ion Concentration; Protein Structure, Tertiary; Photobacterium; Mutation; Binding Sites; Superoxide Dismutase; Protein Subunits; Genetic Engineering; Substrate Specificity