1GN6

G152A mutant of Mycobacterium tuberculosis iron-superoxide dismutase.

1GN6 の概要

• エントリーDOI: 10.2210/pdb1gn6/pdb
• 関連するPDBエントリー: 1GN2 1GN3 1GN4 1IDS
• 分子名称: SUPEROXIDE DISMUTASE, FE (III) ION (3 entities in total)
• 機能のキーワード: oxidoreductase
• 由来する生物種: MYCOBACTERIUM TUBERCULOSIS
• タンパク質・核酸の鎖数: 4
• 化学式量合計: 92522.94

構造登録者

Bunting, K.A.,Cooper, J.B.,Saward, S.,Erskine, P.T.,Badasso, M.O.,Wood, S.P.,Zhang, Y.,Young, D.B. (登録日: 2001-10-03, 公開日: 2001-10-05, 最終更新日: 2024-05-08)

主引用文献

Cooper, J.B.,Saward, S.,Erskine, P.T.,Badasso, M.O.,Wood, S.P.,Zhang, Y.,Young, D.B.
X-Ray Structure Analysis of an Engineered Fe-Superoxide Dismutase Gly-Ala Mutant with Significantly Reduced Stability to Denaturant
FEBS Lett., 387:105-, 1996

PubMed 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 angstroms 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 (phi = 83.1 degrees, psi = -0.3 degrees) close to the left-handed alpha-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 angstroms 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 hydrochloride 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.

PubMed: 8674528
DOI: 10.1016/0014-5793(96)00490-5

実験手法

X-RAY DIFFRACTION (2.9 Å)