2VQD

Crystal Structure of Biotin Carboxylase from Pseudomonas aeruginosa complexed with AMPCP

2VQD の概要

• エントリーDOI: 10.2210/pdb2vqd/pdb
• 関連するPDBエントリー: 2C00 2J9G 2VPQ 2VR1
• 分子名称: BIOTIN CARBOXYLASE, PHOSPHOMETHYLPHOSPHONIC ACID ADENOSYL ESTER, MAGNESIUM ION, ... (5 entities in total)
• 機能のキーワード: nucleotide-binding, fatty acid biosynthesis, lipid synthesis, atp-grasp domain, biotin carboxylase, ligase, biotin, bacteria, atp-binding
• 由来する生物種: PSEUDOMONAS AERUGINOSA
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 51325.31

構造登録者

Mochalkin, I. (登録日: 2008-03-13, 公開日: 2008-09-09, 最終更新日: 2023-12-13)

主引用文献

Mochalkin, I.,Miller, J.R.,Evdokimov, A.,Lightle, S.,Yan, C.,Stover, C.K.,Waldrop, G.L.
Structural Evidence for Substrate-Induced Synergism and Half-Sites Reactivity in Biotin Carboxylase.
Protein Sci., 17:1706-, 2008

PubMed Abstract: Bacterial acetyl-CoA carboxylase is a multifunctional biotin-dependent enzyme that consists of three separate proteins: biotin carboxylase (BC), biotin carboxyl carrier protein (BCCP), and carboxyltransferase (CT). Acetyl-CoA carboxylase is a potentially attractive target for novel antibiotics because it catalyzes the first committed step in fatty acid biosynthesis. In the first half-reaction, BC catalyzes the ATP-dependent carboxylation of BCCP. In the second half-reaction, the carboxyl group is transferred from carboxybiotinylated BCCP to acetyl-CoA to produce malonyl-CoA. A series of structures of BC from several bacteria crystallized in the presence of various ATP analogs is described that addresses three major questions concerning the catalytic mechanism. The structure of BC bound to AMPPNP and the two catalytically essential magnesium ions resolves inconsistencies between the kinetics of active-site BC mutants and previously reported BC structures. Another structure of AMPPNP bound to BC shows the polyphosphate chain folded back on itself, and not in the correct (i.e., extended) conformation for catalysis. This provides the first structural evidence for the hypothesis of substrate-induced synergism, which posits that ATP binds nonproductively to BC in the absence of biotin. The BC homodimer has been proposed to exhibit half-sites reactivity where the active sites alternate or "flip-flop" their catalytic cycles. A crystal structure of BC showed the ATP analog AMPPCF(2)P bound to one subunit while the other subunit was unliganded. The liganded subunit was in the closed or catalytic conformation while the unliganded subunit was in the open conformation. This provides the first structural evidence for half-sites reactivity in BC.

PubMed: 18725455
DOI: 10.1110/PS.035584.108

実験手法

X-RAY DIFFRACTION (2.41 Å)