L-threonine aldolase

Other aldolases, from microorganisms, have been cloned and overexpressed. For instance, L-threonine aldolase from Escherichia coli and D-threonine aldolase from Xanthomonus orysae have been obtained and used to prepare 0-hydroxy-a-amino acid derivatives1122. ... 

The glycine-dependent aldolases contain a cofactor pyridoxal phosphate (PLP). Binding of glycine to it as an imine enables the deprotonation necessary for the carbon-carbon bond forming reaction, with pyridine acting as an electron sink. The subsequent 100% atom efficient reaction with an aldehyde establishes the new bond and two new stereocenters (Scheme 5.30). Of all the glycine-dependent aldolases only L-threonine aldolase (LTA) is commonly used [40, 43, 52]. 

L-Threonine Aldolase (LTA)-Catalyzed Synthesis of L- 3-Hydroxy-a-Amino Acids... 

Scheme 5.50. Synthesis of sialyl Lewis X mimetics using L-threonine aldolase (LTA).

Scheme 5.51. L-Threonine aldolase approach to mycestericin D. X, Rj, R2 = protecting groups.

Scheme 5.52. Structure of vero-toxin recognized RNA sequence (left) and preparation of its peptidic mimetic (right) using LTA (L-threonine aldolase).

Enzyme-catalyzed reactions in this area include reaction with glycine catalyzed by L-threonine aldolase to afford 164 <2000SL1046> and the use of almond oxynitrilase to catalyze the formation of cyanohydrin 165 by reaction of 161 with acetone cyanohydrin <2001T2213>. 

A facile synthesis of (3R,5R)-dihydroxy-L-homoproline, an idulonic acid mimic, was realized using L-threonine aldolase-catalyzed reaction of glycine with an aldehyde derived from L-malic acid [96]. 

A novel serine hydromethyl transferase (SHMT) with L-threonine aldolase activity has been cloned from Streptococcus thermophilus (Vidal et al. 2005b). It was observed that the Km for L-a/to-threonine was 38-fold higher than that for L-threonine, suggesting that this enzyme can be classified as t/treo-selective. The novel aldolase was capable of reacting with unnatural aldehydes for the production of (3-hydroxy-a-amino acids with moderate stereoselectivity. 

The enzymatic aldolization of (/ )-glyceraldehyde acetonide with glycine catalyzed by L-threonine aldolase from Candida humicola gave the key intermediates for the synthesis of 3,4-dihydroxyprolines in six steps (Fujii et al. 2000). 

As mentioned before, one of the main drawbacks in the application of threonine aldolases is their lack of erithro/threo selectivity (kinetic limitation) and their equilibrium position (thermodynamic limitation). Recently, a tandem use of LD-threonine aldolases with low selectivity and L-amino acid decarboxylases with high selectivity has demonstrated to overcome the kinetic and thermodynamic limitations in the synthesis of phenyl serine (Steinreiber et al. 2007). Starting with benzalde-hyde and glycine, i -phenyl ethanol was obtained in 58% isolated yield and R enantiomeric excess higher than 99% by the action of L-threonine aldolase (L-TA) from Pseudomonas putida, D-threonine aldolase (D-TA) from Alcaligenes xylosoxidans and L-tyrosine decarboxylase (L-TyrDC) from Enterococcus faecalis following the scheme depicted in Fig. 6.5.17. 

Scheme 2.196 Aldol reactions catalyzed by L-threonine aldolase...

D- and L-Threonine Aldolase. These enzymes are involved in the biosynthesis/... 

Finally, Griengl s group has developed the synthesis of aromatic 1,2-amino alcohols on the basis of a bienzymatic DYKAT process. The reaction occurred between a benzaldehyde derivative and glycine in the presence of L-threonine aldolase from Pseudomonas putida and L-tyrosine decarboxylase from either Enterococcus faecalis or two genes from Enterococcus faecium. The best results were obtained for the production of (5)-octopamine (99%, ee = 81%), and (5)-noradrenaline (76%, ee = 79%), as shown in Scheme 3.64. 

Aldol reactions have been catalyzed by aldolases as well as by catalytic antibodies. For example, L-threonine aldolase was applied to C—C bond formation of an aldehyde with glycine. The resulting adduct could be further converted to a precursor of N-acetyl-4-deoxy-D-mannosamine, a potent inhibitor of N-acetylneuraminic acid synthetase (Fig. 10.39(a)). "... 

Leuchtenbeiger W, Huthmacher K, Drauz K (2005) Biotechnological production of amino acids and derivatives current status and prospects. Appl Microbiol Biotechnol 69 1-8 Liu JQ, Dairi T, Itoh N, Kataoka M, Shimizu S, Yamada H (1998) Gene cloning, biochemical characterization and physiological characterization of a thermostable low-specificity L-threonine aldolase from Escherichia coli. Eur J Biochem 255 220-226 Livshits VA, Zakataeva NP, Aleshin VV, Vitushkina MV (2003) Identification and characterization of the new gene rhtA involved in threonine and homoserine efflux in Escherichia coli. Res Microbiol 154 123-135... 

Threonine aldolases catalyze the reversible addition of 134 to acetaldehyde to give threonine (137), but the distinction bet veen L-threonine aldolase (ThrA EC 4.1.2.5) and L-aHo-threonine aldolase (EC 4.1.2.6) is vague, because many catalysts have only poor capacity for threo/ erythro discrimination (137/138 Figure 5.61) [284, 291, 292]. In fact, both l- and o-selective enzymes have been purified and cloned from a variety of organisms [284]. The first stereospecific L-aHo-threonine aldolase from Aeromonas jandad has recently been cloned and characterized [293]. X-ray structures of Thermotoga... 

T. Kimura, V.P. Vassilev, G.l. Shen, G.-H. Wong, Enzymatic synthesis of p-hydroxy-a-amino acids based on recombinant D- and L-threonine aldolases, 1. Am. Ghem. Soc. 119 (1997) 11734-11742. 

T. Nishiyama, S.S. Mobile, T. Kajimoto, M. Node, Synthesis of thymine polyoxin C by using L-threonine aldolase-catalyzed aldol reaction. Heterocycles 71 (2007) 1397-1405. 

Miura, T. and Kajimoto, T., Application of L-threonine aldolase-catalyzed reaction to the preparation of protected 3R,5R-dihydroxy-L-homoproline as a mimetic of idulonic acid. Chirality 2001,13 (9), 577-580. 

Shibata, K., Shingu, K., Vassilev, V. R, Nishide, K., Fujita, T., Node, M., Kajimoto, T., and Wong, C.-H., Kinetic and thermodynamic control of L-threonine aldolase catalyzed reaction and its application to the synthesis of mycestericin D. Tetrahedron Lett. 1996,37 (16), 2791-2794. 

Fujii, M., Miura, T., Kajimoto, T., and Ida, Y., Facile S5mthesis of 3,4-dihydroxyprolines as an application of the L-threonine aldolase-catalyzed aldol reaction. Sunlett 2000, 7, 1046-1048. 

Baik, S.-H. and Yoshioka, H., Enhanced synthesis of L-threo-3,4-dihydroxyphenylserine by high-density wholethreonine aldolase from Strepiomyces avermitilis. Biotechnol. Lett. 2009,31 (3), 443 48. 

E. coli whole cells with overexpressed L-threonine aldolase from treptomyces avelmitilis ... 

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