X-ray structure analysis of an engineered Fe-superoxide dismutase Gly-Ala mutant with significantly reduced stability to denaturant

6Citations
Citations of this article
5Readers
Mendeley users who have this article in their library.
Get full text

Abstract

We have refined the X-ray structure of a site-directed G152A mutant of the iron-dependent superoxide dismutase from Mycobacterium tuberculosis at 2.9 Å resolution. The mutation which replaces a glycine residue in a surface loop with alanine was designed to alter the conformation of this loop region which has previously been shown to play a crucial structural role in quaternary interactions within the SOD tetramer, Gly-152 was targeted as it has dihedral angles (φ = 83.1°, ψ = -0.3°) close to the left-handed α-helical conformation which is rarely adopted by other amino acids except asparagine, Gly-152 was replaced by alanine as it has similar size and polarity, yet has a very low tendency to adopt similar conformations, X-ray data collection on crystals of this mutant at 2.9 Å resolution and subsequent least-squares refinement to an R-value of 0.169 clearly establish that the loop conformation is unaffected. Fluorescence studies of guanidine hydrachloride denaturation establish that the mutant is 4 kcal/mol less stable than the wild-type enzyme. Our results indicate that strict conformational constraints imposed upon a region of polypeptide, due for example to interactions with a neighbouring subunit, may force an alanine residue to adopt this sterically hindered conformation with a consequent reduction in stability of the folded conformation.

Cite

CITATION STYLE

APA

Cooper, J. B., Saward, S., Erskine, P. T., Badasso, M. O., Wood, S. P., Zhang, Y., & Young, D. (1996). X-ray structure analysis of an engineered Fe-superoxide dismutase Gly-Ala mutant with significantly reduced stability to denaturant. FEBS Letters, 387(2–3), 105–108. https://doi.org/10.1016/0014-5793(96)00490-5

Register to see more suggestions

Mendeley helps you to discover research relevant for your work.

Already have an account?

Save time finding and organizing research with Mendeley

Sign up for free