Investigation of copper-zinc superoxide dismutase Ser-137 and Ala-137 mutants

Journal Article · Wed Jun 27 00:00:00 EDT 1990 · Inorganic Chemistry; (USA)

DOI:https://doi.org/10.1021/ic00338a004· OSTI ID:6378303

Banci, L; Bertini, I; Viezzoli, M S ^[1]; Cabelli, D ^[2]; Hallewell, R A ^[3]; Luchinat, C ^[4]

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1. Univ. of Florence (Italy)
2. Brookhaven National Laboratory, Upton, NY (USA)
3. Chiron Corporation, Emeryville, CA (USA)
4. Univ. of Bologna (Italy)

Ser- and Ala-137 mutants of human copper-zinc superoxide dismutase (Cu,ZnSOD) have been thoroughly characterized in an attempt to understand the subtle effect of the nature of the residue at position 137 on the structure of the copper site and on the activity profile. The results show that the nature of the residue at position 137 determines the presence of water in the active cavity as monitored through water {sup 1}H nuclear magnetic relaxation dispersion. Also, the hyperfine shifts experienced by the protons of His-48 in the Cu{sub 2}Co{sub 2} derivative are sensitive to the group at the 137 position. These effects are not detected through electronic and EPR spectroscopies. The activity profiles of Ser-137 and Ala-137 mutants are virtually identical and are very close to that of the Ile-137 mutant at pH < 10. The drop in activity above pH 10 closely parallels that observed in the wild type, at variance with the Ile-137 mutant that shows a marked decrease in activity already below pH 10. The activity profiles definitely show evidence of a pK{sub a} between 6 and 7. The affinity of N{sub 3}{sup {minus}} for the Ser-137 and Ala-137 mutants is very similar to that for the wild type. This is again at variance with the Ile-137 derivative that shows an N{sub 3}{sup {minus}} affinity twice as large. 50 refs., 6 figs., 2 tabs.

• OSTI ID: 6378303
• Journal Information: Inorganic Chemistry; (USA), Vol. 29:13; ISSN 0020-1669
• Country of Publication: United States
• Language: English

Related Subjects

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
COPPER COMPOUNDS
MOLECULAR STRUCTURE
MUTANTS
THERMODYNAMIC ACTIVITY
SUPEROXIDE DISMUTASE
ZINC COMPOUNDS
ELECTRONS
EXPERIMENTAL DATA
PULSED IRRADIATION
RADIOLYSIS
CHEMICAL RADIATION EFFECTS
CHEMICAL REACTIONS
CHEMISTRY
DATA
DECOMPOSITION
ELEMENTARY PARTICLES
ENZYMES
FERMIONS
INFORMATION
IRRADIATION
LEPTONS
NUMERICAL DATA
OXIDOREDUCTASES
RADIATION CHEMISTRY
RADIATION EFFECTS
TRANSITION ELEMENT COMPOUNDS
400600* - Radiation Chemistry
400201 - Chemical &amp; Physicochemical Properties