Enatiomerically pure hydroxycarboxylic acids: current approaches and future perspectives

Ren, Qun; Ruth, Katinka; Thöny‐Meyer, Linda; Zinn, Manfred

doi:10.1007/s00253-010-2530-6

Cited by 99 publications

(72 citation statements)

References 134 publications

(126 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Besides the possibility of discerning its role on predator physiology, the interest in the study of PHA hydrolytic enzymes lies in its putative industrial use for the production of chiral R-hydroxyalkanoic acids (RHAs) as building blocks for the synthesis of biobased polymers. These biobased monomers are important chiral starting scaffolds in material, fine chemical, pharmaceutical, and medical industries (7,46). Several bacterial extracellular PHA depolymerases have been identified and characterized so far (4,26,28,29).…”

Section: Discussionmentioning

confidence: 99%

Identification and Biochemical Evidence of a Medium-Chain-Length Polyhydroxyalkanoate Depolymerase in the Bdellovibrio bacteriovorus Predatory Hydrolytic Arsenal

Martínez

Peña

García-Hidalgo

et al. 2012

Appl Environ Microbiol

View full text Add to dashboard Cite

ABSTRACTThe obligate predatorBdellovibrio bacteriovorusHD100 shows a large set of proteases and other hydrolases as part of its hydrolytic arsenal needed for its predatory life cycle. We present genetic and biochemical evidence that open reading frame (ORF) Bd3709 ofB. bacteriovorusHD100 encodes a novel medium-chain-length polyhydroxyalkanoate (mcl-PHA) depolymerase (PhaZBd). The primary structure of PhaZBdsuggests that this enzyme belongs to the α/β-hydrolase fold family and has a typical serine hydrolase catalytic triad (serine-histidine-aspartic acid) in agreement with other PHA depolymerases and lipases. PhaZBdhas been extracellularly produced using different hypersecretor Tol-pal mutants ofEscherichia coliandPseudomonas putidaas recombinant hosts. The recombinant PhaZBdhas been characterized, and its biochemical properties have been compared to those of other PHA depolymerases. The enzyme behaves as a serine hydrolase that is inhibited by phenylmethylsulfonyl fluoride. It is also affected by the reducing agent dithiothreitol and nonionic detergents like Tween 80. PhaZBdis an endoexohydrolase that cleaves both large and small PHA molecules, producing mainly dimers but also monomers and trimers. The enzyme specifically degrades mcl-PHA and is inactive toward short-chain-length polyhydroxyalkanoates (scl-PHA) like polyhydroxybutyrate (PHB). These studies shed light on the potentiality of these predators as sources of new biocatalysts, such as an mcl-PHA depolymerase, for the production of enantiopure hydroxyalkanoic acids and oligomers as building blocks for the synthesis of biobased polymers.

show abstract

Section: Discussionmentioning

confidence: 99%

Identification and Biochemical Evidence of a Medium-Chain-Length Polyhydroxyalkanoate Depolymerase in the Bdellovibrio bacteriovorus Predatory Hydrolytic Arsenal

Martínez

Peña

García-Hidalgo

et al. 2012

Appl Environ Microbiol

View full text Add to dashboard Cite

show abstract

“…6 In the past decades, various types of CSAs for carboxylic acid have been reported, particularly for α-carboxylic acids, such as lanthanide complexes, 7 amines, 8 amino alcohols, 9 diamines, 10 amides, 11 macrocyclic compounds, 12 and ureas(thioureas). 13 However, most of the CSAs are not practical because their 1 H chemical shift nonequivalences are too small to realize baseline resolution.…”

Section: ■ Introductionmentioning

confidence: 99%

A Chiral Bisthiourea as a Chiral Solvating Agent for Carboxylic Acids in the Presence of DMAP

et al. 2013

View full text Add to dashboard Cite

A simple chiral bisthiourea has been used as a highly effective and practical chemical solvating agent (CSA) for diverse α-carboxylic acids in the presence of DMAP. Excellent enantiodiscrimination based on well-resolved α-H NMR signals of the enantiomers of carboxylic acids can be obtained without interference from the chiral bisthiourea and DMAP. To check the practicality of the chiral bisthiourea/ DMAP for enantiomeric determination, the ee values of mandelic acid (MA) samples over a wide ee range were determined by integration of the α-H signal of MA in 1 H NMR. A discrimination mechanism is proposed, that the formation of two diasteromeric ternary complexes between the chiral bisthiourea and two in situ formed enantiomeric carboxylate-DMAPH + ion pairs discriminates the enantiomers of carboxylic acids. Computational modeling studies show that the chemical shift value of α-H of (S)-MA is greater than that of (R)-MA in ternary complexes, which is consistent with experimental observation. 1D and 2D NOESY spectra demonstrate the intermolecular noncovalent interactions between the protons on the aromatic rings of chiral bisthiourea and α-H of the enantiomers of racemic α-methoxy phenylacetic acids in the complexes.

show abstract

“…5A). It is known that the monomers of PHA degradation by PhaZ are typically in the R configuration (49), and the ⌬bktB mutant of H. mediterranei accumulated a considerable amount of PHB instead of PHBV in the cells (20). Thus, PhaZh1 has the potential to produce the chiral compound (R)-3HB, which is a high-value-added product with industrial and medical applications (49).…”

Section: Resultsmentioning

confidence: 99%

A Patatin-Like Protein Associated with the Polyhydroxyalkanoate (PHA) Granules of Haloferax mediterranei Acts as an Efficient Depolymerase in the Degradation of Native PHA

Liu

Hou

Cai

et al. 2015

Appl Environ Microbiol

View full text Add to dashboard Cite

cThe key enzymes and pathways involved in polyhydroxyalkanoate (PHA) biosynthesis in haloarchaea have been identified in recent years, but the haloarchaeal enzymes for PHA degradation remain unknown. In this study, a patatin-like PHA depolymerase, PhaZh1, was determined to be located on the PHA granules in the haloarchaeon Haloferax mediterranei. PhaZh1 hydrolyzed the native PHA (nPHA) [including native polyhydroxybutyrate (nPHB) and native poly(3-hydroxybutyrateco-3-hydroxyvalerate) (nPHBV) in this study] granules in vitro with 3-hydroxybutyrate (3HB) monomer as the primary product. The site-directed mutagenesis of PhaZh1 indicated that Gly 16 , Ser 47 (in a classical lipase box, G-X-S 47 -X-G), and Asp 195 of this depolymerase were essential for its activity in nPHA granule hydrolysis. Notably, phaZh1 and bdhA (encoding putative 3HB dehydrogenase) form a gene cluster (HFX_6463 to _6464) in H. mediterranei. The 3HB monomer generated from nPHA degradation by PhaZh1 could be further converted into acetoacetate by BdhA, indicating that PhaZh1-BdhA may constitute the first part of a PHA degradation pathway in vivo. Interestingly, although PhaZh1 showed efficient activity and was most likely the key enzyme in nPHA granule hydrolysis in vitro, the knockout of phaZh1 had no significant effect on the intracellular PHA mobilization, implying the existence of an alternative PHA mobilization pathway(s) that functions effectively within the cells of H. mediterranei. Therefore, identification of this patatin-like depolymerase of haloarchaea may provide a new strategy for producing the high-value-added chiral compound (R)-3HB and may also shed light on the PHA mobilization in haloarchaea. P olyhydroxyalkanoate (PHA) is accumulated in the form of granules and serves as storage compound of carbon and energy in bacteria (1) and archaea (2) during growth in the presence of excess carbon sources. Several proteins, which are known as PHA granule-associated proteins (PGAPs), are embedded on or attached to the PHA granules. These include PHA synthases, phasins, regulatory proteins, and depolymerases (3). A PHA-accumulating host may utilize the accumulated PHA for growth and survival under conditions of carbon starvation (4). PHA depolymerase (PhaZ) is the key enzyme that functions in PHA mobilization.In bacteria, PHA depolymerases are grouped into two classes: intracellular (catalyzing the degradation of endogenous PHA) (iPhaZ) and extracellular (catalyzing the degradation of exogenous PHA) (ePhaZ) PHA depolymerases (5). The extracellular PHA depolymerase degradation process is well known, but the mechanism underlying the metabolic pathway and regulation of PHA degradation in vivo remains poorly understood (5). Native polyhydroxybutyrate (nPHB) is degraded by iPhaZs in vitro to 3-hydroxybutyrate (3HB) (6, 7) or 3-hydroxybutyryl-coenzyme A (3HB-CoA) in the presence of CoA (8, 9). The PHB degradation product, 3HB-CoA, is the precursor of PHB synthesis; hence, the simultaneous synthesis and mobilization of PHB (10, 11) (8). Notably, th...

show abstract

Enatiomerically pure hydroxycarboxylic acids: current approaches and future perspectives

Cited by 99 publications

References 134 publications

Identification and Biochemical Evidence of a Medium-Chain-Length Polyhydroxyalkanoate Depolymerase in the Bdellovibrio bacteriovorus Predatory Hydrolytic Arsenal

Identification and Biochemical Evidence of a Medium-Chain-Length Polyhydroxyalkanoate Depolymerase in the Bdellovibrio bacteriovorus Predatory Hydrolytic Arsenal

A Chiral Bisthiourea as a Chiral Solvating Agent for Carboxylic Acids in the Presence of DMAP

A Patatin-Like Protein Associated with the Polyhydroxyalkanoate (PHA) Granules of Haloferax mediterranei Acts as an Efficient Depolymerase in the Degradation of Native PHA

Contact Info

Product

Resources

About