ジャーナル: Nature / 年: 2014 タイトル: Structural rearrangements of a polyketide synthase module during its catalytic cycle. 著者: Jonathan R Whicher / Somnath Dutta / Douglas A Hansen / Wendi A Hale / Joseph A Chemler / Annie M Dosey / Alison R H Narayan / Kristina Håkansson / David H Sherman / Janet L Smith / Georgios Skiniotis / 要旨: The polyketide synthase (PKS) mega-enzyme assembly line uses a modular architecture to synthesize diverse and bioactive natural products that often constitute the core structures or complete chemical ...The polyketide synthase (PKS) mega-enzyme assembly line uses a modular architecture to synthesize diverse and bioactive natural products that often constitute the core structures or complete chemical entities for many clinically approved therapeutic agents. The architecture of a full-length PKS module from the pikromycin pathway of Streptomyces venezuelae creates a reaction chamber for the intramodule acyl carrier protein (ACP) domain that carries building blocks and intermediates between acyltransferase, ketosynthase and ketoreductase active sites (see accompanying paper). Here we determine electron cryo-microscopy structures of a full-length pikromycin PKS module in three key biochemical states of its catalytic cycle. Each biochemical state was confirmed by bottom-up liquid chromatography/Fourier transform ion cyclotron resonance mass spectrometry. The ACP domain is differentially and precisely positioned after polyketide chain substrate loading on the active site of the ketosynthase, after extension to the β-keto intermediate, and after β-hydroxy product generation. The structures reveal the ACP dynamics for sequential interactions with catalytic domains within the reaction chamber, and for transferring the elongated and processed polyketide substrate to the next module in the PKS pathway. During the enzymatic cycle the ketoreductase domain undergoes dramatic conformational rearrangements that enable optimal positioning for reductive processing of the ACP-bound polyketide chain elongation intermediate. These findings have crucial implications for the design of functional PKS modules, and for the engineering of pathways to generate pharmacologically relevant molecules.
ダウンロード / ファイル: emd_5664.map.gz / 形式: CCP4 / 大きさ: 26.4 MB / タイプ: IMAGE STORED AS FLOATING POINT NUMBER (4 BYTES)
注釈
Reconstruction of the 5th module from the pikromycin biosynthetic pathway (PikAIII) incubated with methylmalonyl-CoA and thiophenol-pentaketide.
ボクセルのサイズ
X=Y=Z: 2.24 Å
密度
表面レベル
登録者による: 8.699999999999999 / ムービー #1: 8.7
最小 - 最大
-29.12193108 - 40.787982939999999
平均 (標準偏差)
0.0 (±0.99999994)
対称性
空間群: 1
詳細
EMDB XML:
マップ形状
Axis order
X
Y
Z
Origin
-36
-36
-36
サイズ
192
192
192
Spacing
192
192
192
セル
A=B=C: 430.08002 Å α=β=γ: 90.0 °
CCP4マップ ヘッダ情報:
mode
Image stored as Reals
Å/pix. X/Y/Z
2.24
2.24
2.24
M x/y/z
192
192
192
origin x/y/z
0.000
0.000
0.000
length x/y/z
430.080
430.080
430.080
α/β/γ
90.000
90.000
90.000
start NX/NY/NZ
-132
-122
-147
NX/NY/NZ
250
274
261
MAP C/R/S
1
2
3
start NC/NR/NS
-36
-36
-36
NC/NR/NS
192
192
192
D min/max/mean
-29.122
40.788
-0.000
-
添付データ
-
試料の構成要素
-
全体 : The 5th module from the pikromycin biosynthetic pathway (PikAIII)...
全体
名称: The 5th module from the pikromycin biosynthetic pathway (PikAIII) incubated with methylmalonyl-CoA and thiophenol-pentaketide
要素
試料: The 5th module from the pikromycin biosynthetic pathway (PikAIII) incubated with methylmalonyl-CoA and thiophenol-pentaketide
タンパク質・ペプチド: PikAIII
リガンド: Methylmalonyl-CoA
リガンド: Thiophenol-pentaketide
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超分子 #1000: The 5th module from the pikromycin biosynthetic pathway (PikAIII)...
超分子
名称: The 5th module from the pikromycin biosynthetic pathway (PikAIII) incubated with methylmalonyl-CoA and thiophenol-pentaketide タイプ: sample / ID: 1000 詳細: Sample was not frozen prior to loading on the grid. The sample was monodisperse. 集合状態: Dimer / Number unique components: 3