ジャーナル: Nat Commun / 年: 2025 タイトル: Ancestral sequence reconstruction as a tool for structural analysis of modular polyketide synthases. 著者: Taichi Chisuga / Shota Takinami / Zengwei Liao / Masayuki Karasawa / Naruhiko Adachi / Masato Kawasaki / Toshio Moriya / Toshiya Senda / Tohru Terada / Fumitaka Kudo / Tadashi Eguchi / Shogo ...著者: Taichi Chisuga / Shota Takinami / Zengwei Liao / Masayuki Karasawa / Naruhiko Adachi / Masato Kawasaki / Toshio Moriya / Toshiya Senda / Tohru Terada / Fumitaka Kudo / Tadashi Eguchi / Shogo Nakano / Sohei Ito / Akimasa Miyanaga / 要旨: Modular polyketide synthases (PKSs) are large multi-domain enzymes critical for the biosynthesis of polyketide antibiotics. However, challenges with structural analysis limits our mechanistic ...Modular polyketide synthases (PKSs) are large multi-domain enzymes critical for the biosynthesis of polyketide antibiotics. However, challenges with structural analysis limits our mechanistic understanding of modular PKSs. In this report, we explore the potential of ancestral sequence reconstruction (ASR) for structure analysis of target proteins. As a model, we focus on the FD-891 PKS loading module composed of ketosynthase-like decarboxylase (KS), acyltransferase (AT) and acyl carrier protein (ACP) domains. We construct a KSAncAT chimeric didomain by replacing the native AT with an ancestral AT (AncAT) using ASR. After confirming that KSAncAT chimeric didomain retains similar enzymatic function to the native KSAT didomain, we successfully determine a high-resolution crystal structure of the KSAncAT chimeric didomain and cryo-EM structures of the KS-ACP complex. These cryo-EM structures, which could not be determined for the native protein, exemplify the utility of ASR to enable cryo-EM single-particle analysis. Our findings demonstrate that integrating ASR with structural analysis provides deeper mechanistic insight into modular PKSs. Furthermore, applying ASR to a partial region of the targeted multi-domain proteins could expand the potential of ASR and may serve as a valuable framework for investigating the structure and function of various multi-domain proteins.
モノクロメーター: Numerical link type Si(111) double crystal monochromator プロトコル: SINGLE WAVELENGTH / 単色(M)・ラウエ(L): M / 散乱光タイプ: x-ray
放射波長
波長: 1 Å / 相対比: 1
反射
解像度: 2→50 Å / Num. obs: 81441 / % possible obs: 99.9 % / 冗長度: 7.9 % / CC1/2: 0.999 / Rmerge(I) obs: 0.065 / Net I/σ(I): 15.4
反射 シェル
解像度: 2→2.04 Å / Rmerge(I) obs: 1.35 / Mean I/σ(I) obs: 1.5 / Num. unique obs: 4265 / CC1/2: 0.774 / % possible all: 98
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解析
ソフトウェア
名称
バージョン
分類
REFMAC
5.8.0238
精密化
XDS
データ削減
Aimless
データスケーリング
MOLREP
位相決定
Coot
モデル構築
精密化
構造決定の手法: 分子置換 / 解像度: 2→48.21 Å / Cor.coef. Fo:Fc: 0.966 / Cor.coef. Fo:Fc free: 0.948 / SU B: 12.176 / SU ML: 0.149 / 交差検証法: THROUGHOUT / ESU R: 0.144 / ESU R Free: 0.144 / 立体化学のターゲット値: MAXIMUM LIKELIHOOD / 詳細: HYDROGENS HAVE BEEN ADDED IN THE RIDING POSITIONS
Rfactor
反射数
%反射
Selection details
Rfree
0.24612
4063
5 %
RANDOM
Rwork
0.20144
-
-
-
obs
0.20361
77202
99.78 %
-
溶媒の処理
イオンプローブ半径: 0.8 Å / 減衰半径: 0.8 Å / VDWプローブ半径: 1.2 Å / 溶媒モデル: MASK