Assignment of backbone NMR resonances and secondary structural elements of a reduced monomeric mutant of copper/zinc superoxide dismutase
✍ Scribed by Lucia Banci; Marco Benedetto; Ivano Bertini; Rebecca Del Conte; Mario Piccioli; Thierry Richert; Maria Silvia Viezzoli
- Publisher
- John Wiley and Sons
- Year
- 1997
- Tongue
- English
- Weight
- 710 KB
- Volume
- 35
- Category
- Article
- ISSN
- 0749-1581
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✦ Synopsis
An extensive series of three-dimensional, triple resonance experiments were performed on a fully labeled 13C, 15N monomeric form of human copper/zinc superoxide dismutase which contains 153 amino acids. The present system, in addition to the mutations at the subunit-subunit interface (Phe50 Ç Glu, Gly51 Ç Glu) which lead to the monomeric form, carries the mutation of the Glu133 to Gln, a residue at the active channel entrance. Firm assignment was found for 97% of the protons, 99% of the 13Ca, 91% of the 15N, 98% of 13C(O) and 90% of the 13Cb backbone resonances. Analysis of the chemical shift values of 13Ca, Ha, 13Cb and 13CO, of coupling 3J HNHa constants, of NOEs between backbone protons and of the H-D exchange behavior of amide protons permits the unequivocal detection of elements of secondary structure. The secondary structure of the present monomeric form is very similar to that of the WT enzyme, although the enzymatic activity is 20% of that of the WT protein.