Thioesterase

Scheme 10.8 Biosynthesis of epothilone. Individual PKS domains are represented as circles and individual NRPS domains as hexagons. Acyl carrier proteins (ACPs) and thiola-tion domains (T) are posttranslationally modified by a phos-phopantetheinyl group to which the biosynthetic intermediates are covalently bound throughout the chain assembly. The thioesterase domain (TE) cyclizes the fully assembled carbon chain to give the 16-membered lactone. Following dehydration of Cl 2—Cl 3 to give epothilones C and D, the final step in epothilone biosynthesis is the epoxidation of the C12=C13 double bond by the cytochrome P450 enzyme P450epol<. KS ketosyn-thase KS(Y) active-site tyrosine mutant of KS AT acyltransfer-ase C condensation domain A adenylation domain ...

Oilseed rape (Canola) Calgene/1992 12 0 Acyl carrier protein thioesterase Umbellularia californica (California Bay) High-laurate canola oil... 

Figure 11.2 Biosynthesis of the nine-membered enediynes. Members of this family share a common biosynthetic pathway for the enediyne core intermediate. Domains are shown in circles with abbreviations (KS, ketosynthase AT, acyltransferase KR, ketoreductase DH, dehydratase TE, thioesterase ACP, acyl carrier protein PPT, phosphopantetheine transferase)...

Figure 11.5 Amino acid building blocks are incorporated into daptomycin backbone successively by NRPS subunits DptA, DptBC and DptD (a). Structural diversity of daptomycin peptide core can be obtained by genetic modifications of dpt gene cluster (b). C, condensation domain A, adenylation domain PCP, peptidyl carrier protein E, epimerase TE, thioesterase domain... 

Gokhale, R.S., Hunziker, D., Cane, D.E. and Khosla, C. (1999) Mechanism and specificity of the terminal thioesterase domain from the erythromycin polyketide synthase. Chemistry Biology, 6, 117. 

Trauger, J.W., Kohli, R.M. and Walsh, C.T. (2001) Cyclization of backbone-substituted peptides catalyzed by the thioesterase domain from the tyrocidine nonribosomal peptide synthetase. Biochemistry, 40 (24), 7092-7098. 

Lu, H., Tsai, S.-C., Khosla, C. and Cane, D.E. (2002) Expression, site-directed mutagenesis, and steady state kinetic analysis of the terminal thioesterase domain of the methymycin/picromycin polyketide synthase. Biochemistry, 41, 12590-12597. 

Boddy, C.N., Schneider, T.L., Hotta, K. et al. (2003) Epothilone C macrocyclization and hydrolysis are catalyzed by the isolated thioesterase domain of epothilone polyketide synthase. Journal of the American Chemical Society, 125, 3428-3429. 

It is worth mentioning that metabolic engineering of E. coli recently provided recombinant strains which synthesized PHAMCL from gluconate. For this, beside phaC2Po or phaClPa> the thioesterase I from E. coli (TesA) [128] or the acyl-ACP thioesterase from Umbellularia californica [129], respectively, were expressed in E. coli. However, the amounts of PHAMCL accumulated in the cells were rather low, and this artificial pathway was not very efficient. 

Fig. 4. Modification of plant metabolic pathways for the synthesis of poly(3HAMCL) in peroxisomes. The pathways created or enhanced by the expression of transgenes (P. aeruginosa PHA synthase and C. lanceolata decanoyl-ACP thioesterase) and of mutant alleles of plant fatty acid desaturase genes are highlighted by bold arrows and the enzymes involved underlined...

Modulation of the quantity and/or quality of poly(3HAMCL) synthesized in peroxisomes was also achieved by modifying the endogenous fatty acid biosynthetic pathway [58]. For example, expression of the peroxisomal PHA synthase in an A. thaliana mutant deficient in the synthesis of triunsaturated fatty acids [59] resulted in the synthesis of a PHA having an almost complete absence of triunsaturated 3-hydroxyacid monomers [58]. In a different strategy, expression of a fatty acyl-ACP thio esterase in the plastid was combined with the expression of a peroxisomal PHA synthase [58]. Fatty acyl-ACP thioesterases are... 

Grunewald, J., Kopp, F., Mahlert, C., Linne, U., Sieber, S. A. and Marahiel, M. A. (2005). Fluorescence resonance energy transfer as a probe of peptide cyclization catalyzed by nonribosomal thioesterase domains. Chem. Biol. 12, 873-881. 

Infantile neuronal ceroid lipofuscinosis (CLN1) Autosomal recessive Palmitooylprotein thioesterase... 

Infantile neuronal ceroid lipofuscinosis CNL1 Palmitoyl protein thioesterase Saposins... 

The neuronal ceroid lipofuscinoses (CLN), also referred to as Batten s disease, are a group of disorders characterized by the accumulation of autofluorescent lipopigments. Clinical hallmarks include blindness, seizures, cognitive and motor decline and early death. Age of onset varies from infancy to adulthood. Eight genetic forms have been identified [4]. Two involve lysosomal acid hydrolases. CLN1 codes for palmitoyl protein thioesterase 1. Clinically it presents most often in infancy and leads to loss of active movement and visual contact by 3 years of age. It is most common in Finland, where its incidence is 1 20,000. CLN2 codes for a lysosomal pepstatin-insensitive acid protease. 

S. E. H. Alexson, R. Mentlein, C. Wernstedt, U. Hellmann, Isolation and Characterization of Microsomal Acyl-CoA Thioesterase - A Member of the Liver Microsomal Carboxylesterase Multi-Gene Family , Eur. J. Biochem. 1993, 214, 719-727. 

J. Hempel, H. Nicholas, H. Jomvall, Thiol Proteases and Aldehyde Dehydrogenases Evolution from a Common Thioesterase Precursor , Proteins Struct., Funct., Genet. 1991,11, 176-183. 

Phosphopantetheine tethering is a posttranslational modification that takes place on the active site serine of carrier proteins - acyl carrier proteins (ACPs) and peptidyl carrier proteins (PCPs), also termed thiolation (T) domains - during the biosynthesis of fatty acids (FAs) (use ACPs) (Scheme 23), polyketides (PKs) (use ACPs) (Scheme 24), and nonribosomal peptides (NRPs) (use T domain) (Scheme 25). It is only after the covalent attachment of the 20-A Ppant arm, required for facile transfer of the various building block constituents of the molecules to be formed, that the carrier proteins can interact with the other components of the different multi-modular assembly lines (fatty acid synthases (FASs), polyketide synthases (PKSs), and nonribosomal peptide synthetases (NRPSs)) on which the compounds of interest are assembled. The structural organizations of FASs, PKSs, and NRPSs are analogous and can be divided into three broad classes the types I, II, and III systems. Even though the role of the carrier proteins is the same in all systems, their mode of action differs from one system to another. In the type I systems the carrier proteins usually only interact in cis with domains to which they are physically attached, with the exception of the PPTases and external type II thioesterase (TEII) domains that act in trans. In the type II systems the carrier proteins selectively interact... 

Scheme 23 Example of an acyl carrier protein (ACP in red) in a type I FAS. The palmitic acid is depicted as a representative fatty acid. During its biosynthesis, the ACP (red) interacts iteratively with each domain (DH, dehydrogenase ER, enoyl reductase KR, ketoreductase KS, ketosynthase TE, thioesterase) until the palmitic acid has reached its proper length.

C domains that oatalyzed the formation of multiple amide bonds Transglutaminases Chain Termination Strategies Thioesterase-catalyzed chain release Alternative chain release through reduction Condensation domains as chain termination catalysts Diketopiperazine formation Oxidative ohain termination... 

Structure and Function of Peptidyl Carrier Protein Domains Structure and Function of Adenylation Domains Structure and Function of Condensation Domains Structure and Function of Thioesterase Domains Multidomain NRPS Structural Information PCP-C didomain structure PCP-TE didomain structure Structure of a C-A-PCP-TE termination module Pathways to Nonproteinogenic Amino Acids Incorporated into NRP Natural Nonproteinogenic Amino Acids Present as Cellular Metabolites Modification of Proteinogenic Amino Acids Nonproteinogenic Amino Acids Derived from Multistep Pathways Tailoring Enzymology in NRP Natural Products Chemical Approaches Toward Mechanistic Probes and Inhibitors of NRPS... 

Figure 7 Biosynthesis of coeiicheiin by the noniinear coeiicheiin synthetase. Chain reiease is cataiyzed by the frans-acting thioesterase, CchJ.

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