Structural Basis for Substrate Recognition and Specificity in Aklavinone-11-Hydroxylase from Rhodomycin Biosynthesis

Structure and Mutation Analysis of Archaeal Geranylgeranyl Reductase

“…31 The most similar structure is Ta-GGR (Z N 40) as expected. Sarcosine oxidases [32][33][34] , p-hydroxybenzoate hydroxylases 35,36 , halogenases [37][38][39][40][41] and several monooxygenases and oxygenases [42][43][44][45][46][47][48][49][50][51][52] are also very similar to Sa-GGR (Z N 20). Many of these Z N 20 proteins have one FAD molecule (or artificially replaced cofactors) in each related subunit, and …”

“…Since the Sa-GGR C-terminal part is ∼ 60 residues longer than those in Ta-GGR, we consider this part to be the independent domain. It should be noted that both two-and threedomain enzymes are known in PHBH family enzymes, 29,32,43,45,[47][48][49][50]52,55 and the total amino acid chain length of the two-domain enzymes is typically 50-70 residues shorter than that of Sa-GGR. 29,32,45,50,55 Structural alignment shows that conserved residues are distributed in only the FADbinding domain (Supplementary Data Fig.…”

Catalytic and Structural Features of Flavoprotein Hydroxylases and Epoxidases

“…Recently, several structures for flavoprotein polyketide hydroxylases were solved. [25,29] Among these enzymes, PgaE and CabE are involved in gaudimycin C biosynthesis in Streptomyces species [Scheme 2 (A)], whereas aklavinone 11-hydroxylase (RdmE) is involved in the biosynthesis of rhodomycin in Streptomyces purpurascens [Scheme 2 (B)].…”

“…This selectivity is explained by the presence of a pocket next to the C-7 hydroxy group that produces several clashes if carbohydrate atoms are modelled. [29] In vitro studies with PgaE illustrate that conversion of UWM6 into gaudimycin C requires multiple coupled reactions to prevent intermediate degradation, complicating detailed biochemical studies. [51] Nevertheless, more information regarding the substrate specificity and evolution potential could help in determining the synthetic and catalytic value of these polyketide hydroxylases.…”

“…Structural and rapid kinetics studies on wild-type and engineered enzyme variants elucidated many details of the catalytic cycle of PHBH. Moreover, these investigations revealed that the isoalloxazine ring of the FAD cofactor is mobile and can swing in and out of [19,20] A 1PN0; 1FOH phenol 2-monooxygenase (PHHY) [22,23] A 2DKH; 2DKI 3-hydroxybenzoate 4-hydroxylase (MHBH) [24] A 2 A1; 2 A2 UW16 12-hydroxylase (PgaE/CabE) [25] A 2R0C; 2R0G; 2R0P 7-carboxy-K252c hydroxylase (RebC) [26] A 2VOU 2,6-dihydroxypyridine 3-hydroxylase (DHP) [27] A 2RGJ phenazine-1-carboxylate hydroxylase (PhzS) [28] A 3IHG aklavinone 11-hydroxylase (RdmE) [29] A 3GMB; 3GMC 2-methyl-3-hydroxypyridine-5-carboxylic acid oxygenase (MHPCO) [30] E 3IHM styrene monooxygenase (StyA) [9] Scheme 1. Reactions catalyzed by (A) PHBH, (B) PHHY, (C) MHBH, (D) DHP hydroxylase.…”