1FWG

KLEBSIELLA AEROGENES UREASE, C319S VARIANT

1FWG の概要

• エントリーDOI: 10.2210/pdb1fwg/pdb
• 分子名称: UREASE, NICKEL (II) ION, ... (5 entities in total)
• 機能のキーワード: hydrolase(urea amido), mutant, nickel metalloenzyme, hydrolase
• 由来する生物種: Klebsiella aerogenes; 詳細
• 細胞内の位置: Cytoplasm (By similarity): P18316 P18315 P18314
• タンパク質・核酸の鎖数: 3
• 化学式量合計: 83323.84

構造登録者

Pearson, M.A.,Karplus, P.A. (登録日: 1997-04-23, 公開日: 1997-10-15, 最終更新日: 2021-11-03)

主引用文献

Pearson, M.A.,Michel, L.O.,Hausinger, R.P.,Karplus, P.A.
Structures of Cys319 variants and acetohydroxamate-inhibited Klebsiella aerogenes urease.
Biochemistry, 36:8164-8172, 1997

PubMed Abstract: Cys319 is located on a mobile flap covering the active site of Klebsiella aerogenes urease but does not play an essential role in catalysis. Four urease variants altered at position C319 range from having high activity (C319A) to no measurable activity (C319Y), indicating Cys is not required at this position, but its presence is highly influential [Martin, P. R., & Hausinger, R. P. (1992) J. Biol. Chem. 267, 20024-20027]. Here, we present 2.0 A resolution crystal structures of C319A, C319S, C319D, and C319Y proteins and the C319A variant inhibited by acetohydroxamic acid. These structures show changes in the hydration of the active site nickel ions and in the position and flexibility of the active site flap. The C319Y protein exhibits an alternate conformation of the flap, explaining its lack of activity. The changes in hydration and conformation suggest that there are suboptimal protein-solvent and protein-protein interactions in the empty urease active site which contribute to urease catalysis. Specifically, we hypothesize that the suboptimal interactions may provide a significant source of substrate binding energy, and such hidden energy may be a common phenomenon for enzymes that contain mobile active site loops and undergo an induced fit. The acetohydroxamic acid-bound structure reveals a chelate interaction similar to those seen in other metalloenzymes and in a small molecule nickel complex. The inhibitor binding mode supports the proposed mode of urea binding. We complement these structural studies with extended functional studies of C319A urease to show that it has enhanced stability and resistance to inhibition by buffers containing nickel ions. The near wild-type activity and enhanced stability of the C319A variant make it useful for further studies of urease structure-function relationships.

PubMed: 9201965
DOI: 10.1021/bi970514j

実験手法

X-RAY DIFFRACTION (2 Å)