Structural Enzymological Studies of 2-Enoyl Thioester Reductase of the Human Mitochondrial FAS II Pathway: New Insights into Its Substrate Recognition Properties

Chen, Zhijun; Pudas, R.; Sharma, Satyan; Smart, Oliver S.; Juffer, André H.; Hiltunen, J. Kalervo; Wierenga, Rik K.; Haapalainen, Antti M.

doi:10.1016/j.jmb.2008.04.041

Cited by 44 publications

(50 citation statements)

References 69 publications

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“…In contrast, in bovine -crystallin, which shows minimal QOR activity, the corresponding residue is a His, suggesting that the Tyr is essential in the kinetic mechanism (51). In addition, mutagenesis and/or structural data support the participation of a Tyr in the mechanism of the related, Zn 2ϩ -lacking MDRs (Table 2) enoyl reductase (39,47), Arabidopsis NADP-dependent oxidoreductase P1, and leukotriene B 4 12-hydroxydehydrogenase (45,46). Thus, it was appropriate to propose a catalytic role for PIG3 Tyr-51, the only Tyr residue in the active-site cavity, further supported by a docking model (Fig.…”

Section: Discussionmentioning

confidence: 86%

“…The catalytic domain is dominated by a sevenstranded antiparallel ␤-sheet, whereas the cofactor-binding domain consists of two mononucleotide binding ␤␣␤␣␤ motifs, which are assembled into the classical Rossmann fold. However, there is an additional ␤-strand (␤*), which was also described in the human enoyl thioester reductase (39).…”

Section: Substrate Analysis Of Pig3 and Cofactor Specificity-mentioning

confidence: 87%

“…Site-directed Mutagenesis of the Active Site Tyr-In several Zn 2ϩ -independent MDRs, evidence supports a Tyr residue acting as an acid/base catalyst (39,(45)(46)(47). The crystallographic structures suggest that Tyr-51 in PIG3 and Tyr-59 in -crystallin are candidates to perform this catalytic function.…”

Section: Nadpmentioning

confidence: 99%

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Three-dimensional Structure and Enzymatic Function of Proapoptotic Human p53-inducible Quinone Oxidoreductase PIG3

Porté

Valencia

Yakovtseva

et al. 2009

Journal of Biological Chemistry

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Tumor suppressor p53 regulates the expression of p53-induced genes (PIG) that trigger apoptosis. PIG3 or TP53I3 is the only known member of the medium chain dehydrogenase/reductase superfamily induced by p53 and is used as a proapoptotic marker. Although the participation of PIG3 in the apoptotic pathway is proven, the protein and its mechanism of action were never characterized. We analyzed human PIG3 enzymatic function and found NADPH-dependent reductase activity with ortho-quinones, which is consistent with the classification of PIG3 in the quinone oxidoreductase family. However, the activity is much lower than that of -crystallin, a better known quinone oxidoreductase. In addition, we report the crystallographic structure of PIG3, which allowed the identification of substrate-and cofactor-binding sites, with residues fully conserved from bacteria to human. Tyr-59 in -crystallin (Tyr-51 in PIG3) was suggested to participate in the catalysis of quinone reduction. However, kinetics of Tyr/Phe and Tyr/Ala mutants of both enzymes demonstrated that the active site Tyr is not catalytic but may participate in substrate binding, consistent with a mechanism based on propinquity effects. It has been proposed that PIG3 contribution to apoptosis would be through oxidative stress generation. We found that in vitro activity and in vivo overexpression of PIG3 accumulate reactive oxygen species. Accordingly, an inactive PIG3 mutant (S151V) did not produce reactive oxygen species in cells, indicating that enzymatically active protein is necessary for this function. This supports that PIG3 action is through oxidative stress produced by its enzymatic activity and provides essential knowledge for eventual control of apoptosis.

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Section: Discussionmentioning

confidence: 86%

Section: Substrate Analysis Of Pig3 and Cofactor Specificity-mentioning

confidence: 87%

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Three-dimensional Structure and Enzymatic Function of Proapoptotic Human p53-inducible Quinone Oxidoreductase PIG3

Porté

Valencia

Yakovtseva

et al. 2009

Journal of Biological Chemistry

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“…In all cases, enzymes of the mitochondrial FAS pathway (KAS/ CEM1, HTD2, and MECR/ETR1) show broad substrate specificity with regard to chain length. The active sites accept substrates with short chains (C 2 ) all the way up to C 14 -16 fatty acid derivatives (22,32,33). Interestingly, the recently published crystal structure of human MECR/ETR1 revealed a ligandbinding pocket deep enough to accommodate acyl groups up to 16 carbons in chain length (33).…”

Section: Lipoic Acid and Beyondmentioning

confidence: 99%

“…The active sites accept substrates with short chains (C 2 ) all the way up to C 14 -16 fatty acid derivatives (22,32,33). Interestingly, the recently published crystal structure of human MECR/ETR1 revealed a ligandbinding pocket deep enough to accommodate acyl groups up to 16 carbons in chain length (33). These observations of activesite pocket size suggest that the mitochondrial FAS pathway may produce fatty acids longer than octanoic acid.…”

Section: Lipoic Acid and Beyondmentioning

confidence: 99%

Mitochondrial Fatty Acid Synthesis Type II: More than Just Fatty Acids

Hiltunen

Schonauer

Autio

et al. 2009

Journal of Biological Chemistry

154

134

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Eukaryotes harbor a highly conserved mitochondrial pathway for fatty acid synthesis (FAS), which is completely independent of the eukaryotic cytosolic FAS apparatus. The activities of the mitochondrial FAS system are catalyzed by soluble enzymes, and the pathway thus resembles its prokaryotic counterparts. Except for octanoic acid, which is the direct precursor for lipoic acid synthesis, other end products and functions of the mitochondrial FAS pathway are still largely enigmatic. In addition to low cellular levels of lipoic acid, disruption of genes encoding mitochondrial FAS enzymes in yeast results in a respiratory-deficient phenotype and small rudimentary mitochondria. Recently, two distinct links between mitochondrial FAS and RNA processing have been discovered in vertebrates and yeast, respectively. In vertebrates, the mitochondrial 3-hydroxyacyl-acyl carrier protein dehydratase and the RPP14 subunit of RNase P are encoded by the same bicistronic transcript in an evolutionarily conserved arrangement that is unusual for eukaryotes. In yeast, defects in mitochondrial FAS result in inefficient RNase P cleavage in the organelle. The intersection of mitochondrial FAS and RNA metabolism in both systems provides a novel mechanism for the coordination of intermediary metabolism in eukaryotic cells.

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Fatty Acid Biosynthesis: Chain‐Length Regulation and Control

et al. 2019

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De novo biosynthesis of fatty acids is an iterative process requiring strict regulation of the lengths of the produced fatty acids. In this review, we focus on the factors determining chain lengths in fatty acid biosynthesis. In a nutshell, the process of chain‐length regulation can be understood as the output of a chain‐elongating C−C bond forming reaction competing with a terminating fatty acid release function. At the end of each cycle in the iterative process, the synthesizing enzymes need to “decide” whether the growing chain is to be elongated through another cycle or released as the “mature” fatty acid. Recent research has shed light on the factors determining fatty acid chain length and has also achieved control over chain length for the production of the technologically interesting short‐chain (C4–C8) and medium‐chain (C10–C14) fatty acids.

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Structural Enzymological Studies of 2-Enoyl Thioester Reductase of the Human Mitochondrial FAS II Pathway: New Insights into Its Substrate Recognition Properties

Cited by 44 publications

References 69 publications

Three-dimensional Structure and Enzymatic Function of Proapoptotic Human p53-inducible Quinone Oxidoreductase PIG3

Three-dimensional Structure and Enzymatic Function of Proapoptotic Human p53-inducible Quinone Oxidoreductase PIG3

Mitochondrial Fatty Acid Synthesis Type II: More than Just Fatty Acids

Fatty Acid Biosynthesis: Chain‐Length Regulation and Control

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