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Teicoplanin
Systematic (IUPAC) name
Ristomycin A 34-O-[2-(acetylamino)-2-deoxy-.beta.-D-glucopyranosyl]-22,31-dichloro-7-demethyl-64-O-demethyl-19-deoxy-56-O-[2-deoxy-2-[(8-methyl-1-oxononyl)amino]-.beta.-D-glucopyranosyl]-42-O-.alpha.-D-mannopyranosyl-
Identifiers
CAS number 61036-62-2
ATC code J01XA02
Chemical data
Formula Variable
Mol. mass 1564.3 to 1907.7 g/mol
Pharmacokinetic data
Bioavailability 90% (given IM)
Protein binding 90% to 95%
Metabolism Nil
Half life 70 to 100 hours
Excretion Renal (97% unchanged)
Therapeutic considerations
Pregnancy cat. B3(AU)
Legal status POM (UK)
Routes Intravenous, intramuscular

Teicoplanin is an antibiotic used in the prophylaxis and treatment of serious infections caused by Gram-positive bacteria, including methicillin-resistant Staphylococcus aureus and Enterococcus faecalis. It is a glycopeptide antiobiotic extracted from Actinoplanes teichomyceticus, with a similar spectrum of activity to vancomycin. Its mechanism of action is to inhibit bacterial cell wall synthesis. Teicoplanin is marketed by Sanofi-Aventis under the trade name Targocid.

Oral teicoplanin has been demonstrated to be effective in the treatment of pseudomembranous colitis and Clostridium difficile-associated diarrhoea, with comparable efficacy with vancomycin.[1]

Its strength is considered to be due to the length of the hydrocarbon chain.[2]

Contents

Chemistry

Teicoplanin (TARGOCID , marketed by Sanofi Aventis Ltd) is actually a mixture of several compounds, five major (named teicoplanin A2-1 through A2-5) and four minor (named teicoplanin RS-1 through RS-4).[3] All teicoplanins share a same glycopeptide core, termed teicoplanin A3-1 — a fused ring structure to which two carbohydrates (mannose and N-acetylglucosamine) are attached. The major and minor components also contain a third carbohydrate moietyβ-D-glucosamine — and differ only by the length and conformation of a side chain attached to it.

The structures of the teicoplanin core and the side chains which characterize the five major teicoplanin compounds are shown below.

Teicoplanin core (left, black) and side chains which characterize teicoplanins A2-1 through A2-5 (right). In blue: β-D-glucosamine.

Biosynthesis

Teicoplanin consists of a group of five structures. These structures share a common aglycone, or core, consisting of seven amino acids that are bound by peptide and ether bonds to form a four ring system. These five structures differ by the identity of the fatty acyl side chain attached to the sugar. The origin of these seven amino acids in the biosynthesis of teicoplanin was studied by 1H and 13C NMR.[4] The studies indicate amino acids AA1, AA2, AA4, AA5, and AA6 are derived from tyrosine, and amino acids AA3 and AA7 are derived from acetate. Specifically, teicoplanin contains 4-hydroxyphenylglycine and 3,5-dihydroxyphenylglycine residues, a chlorine atom attached on each of the tyrosine residues, and three sugar moieties, N-fatty acyl-β-D-glucosamine, N-acetyl-β-D-glucosamine, and D-mannose.

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Gene Cluster

The study of the genetic cluster encoding the biosynthesis of teicoplanin identified forty nine putative open reading frames (orf) involved in the compound's biosynthesis, export, resistance, and regulation. Thirty-five of these orfs are similar to those found in other glycopeptide gene clusters. The function of each of these genes is described by Li and co-workers.[5]. A summary of the gene layout and purpose is shown below.

Gene layout. The genes are numbered. The letters L and R designate transcriptional direction The presence of the * symbol means a gene is found after NRPS, which are represented by A, B, C, and D. Based on the figure from: Li, T-L.; Huang, F.; Haydock, S. F.; Mironenko, T.; Leadlay, P. F.; Spencer, J. B. Chemistry & Biology. 2004, 11, p. 109.

[11-L] [10-L] [9-R] [8-R] [7-R] [6-R] [5-R] [4-L][3-L] [2-L] [1-R] [A-R] [B-R] [C-R] [D-R] [1*-R] [2*-R] [3*-R] [4*-R] [5*-R] [6*-R] [7*-R] [8*-R] [9*-R] [10*-R] [11*-R] [12*-R] [13*-R] [14*-R] [15*-R] [16*-R] [17*-R] [18*-R] [19*-R] [20*-R] [21*-R] [22*-R] [23*-R] [24*-R] [25*-L] [26*-L] [27*-R] [28*-R] [29*-R] [30*-R][31*-R] [32*-L] [33*-L] [34*-R]

Enzyme Produced By Gene Sequence Regulatory Proteins Other Enzymes Resistant Enzymes Β-hydroxy-tyrosine and 4-hydroxy-phenylglycin biosynthetic enzymes Glycosyl Transferases Peptide Synthetases P450 Oxygenases Halogenase 3,5-dihydroxy phenylglycin biosynthetic enzymes
Genes 11, 10, 3, 2, 15*, 16*, 31* 9, 8, 1*, 2*, 4*, 11*, 13*, 21*, 26*, 27*, 30*, 32*, 33*, 34* 7, 6, 5 4, 12*, 14*, 22*, 23*, 24*, 25*, 28*, 29* 1, 3*, 10* A, B, C, D 5*, 6*, 7*, 9* 8* 17*, 18*, 19*, 20*, 23*

Heptapeptide Backbone Synthesis

Analysis indicated tyrosine and three types of nonproteinogenic amino acids, (S)-4-hydroxyphenylglycine, 3,5-dihydroxyphenylglycine, and β-hydroxytyrosine as the building blocks of the teicoplanin group of glycopeptides. In all, six of the seven total amino acids of the teicoplanin backbone are composed of nonproteinogenic or modified amino acids. It has been found that eleven enzymes are coordinatively induced to produce these six required residues.[6] Teicoplanin contains two chlorinated positions on teicoplanin, 2 (3-Cl-Tyr) and 6 (3-Cl-β-Hty). It has been proposed that the putative halogenase Orf8* catalyzes the halogenation on both amino acids. It is thought chlorination occurs at a very early point in the biosynthesis prior to phenolic oxidative coupling, with the possibility of tyrosine or β-hydroxytyrosine being the substrate of chlorination.

The biosynthesis of the heptapeptide backbone is carried out by four nonribosomal peptide synthetases designated TeiA, TeiB, TeiC, and TeiD. Each of the modules has a domain for amino acid selection and activation as the aminoacyl-AMP. The catalytic domains in modules one and three of the nonribosomal peptide synthetase assemply line select and activate (S)-4-hydroxyphenylglycine and 3,5-dihydroxyphenylglycine.[6] In addition to these modules for amino acid selection and activation, each module has a thiolation domain modified with phosphopantetheine to provide a thiol for covalent aminoacyl-S-enzyme formation. The third domain in each module is the condensation domain, which catalyzes the formation of the amide bonds.

Post-Heptapeptide Backbone Formation Modification

Once the heptapeptide backbone has been formed, the cylcization of the linear structure is begun.[7] Gene disruption studies indicate a cytochrome P450 oxygenase as the enzyme that performs the coupling reactions. OxyB has been suggested to form the first ring by coupling residues 4 and 6. OxyA then couples residues 2 and 4, followed by the formation of a C-C bond between residues 5 and 7 by OxyC. A fourth enzyme catalyzes the coupling of residues 1 and 3, although where this coupling fits into the OxyB/OxyA/OxyC order is not known. It has been suggested that the regioselectivity and atropisomer selectivity of these propable one-electron coupling reactions is due to the folding and orientation requirements of the partially crossed-linked substrates in the enzyme active site.[7]. The coupling reactions are shown below.

Oxidative Coupling Of Teicoplanin Backbone

Specific glycosylation has been shown to occur after the formation of the heptpeptide aglycone.[8] Data suggests there are three separate glycosyl transferases required for the glycosylation of the teicoplanin aglycone. Two of these glycosyl transferases are involved in the addition of the N-fatty acyl-β-D-glucosamine and N-acetyl-β-D-glucosamine units. A third mannosyl transferase is responsible for the addition of the D-mannose unit onto residue 7. The fatty acyl chain is connected by amide bond to the glucosamine moiety by the action of an acyl transferase. In addition to glycosylation, it has been suggested that some genes code for deacetylases.[9] In addition to the ability to salvage portions of the molecular structure, it provides a way to protect/deprotect the molecule.

References

  1. ^ de Lalla F, Nicolin R, Rinaldi E, Scarpellini P, Rigoli R, Manfrin V, Tramarin A (1992). "Prospective study of oral teicoplanin versus oral vancomycin for therapy of pseudomembranous colitis and Clostridium difficile-associated diarrhoea". Antimicrob Agents Chemother 36 (10): 2192–6. PMID 1444298. 
  2. ^ Gilpin M, Milner P (1997). "Resisting changes -- Over the past 40 years the glycopeptide antibiotics have played a crucial role in treating bacterial infections. But how long can it continue ?". Royal Society of Chemistry. http://www.chemsoc.org/chembytes/ezine/1997/resist.htm. Retrieved 2006-10-15.  - includes picture of Teicoplanin's structure.
  3. ^ Bernareggi A, Borghi A, Borgonovi M, Cavenaghi L, Ferrari P, Vékey K, Zanol M, Zerilli L (1 August 1992). "Teicoplanin metabolism in humans". Antimicrob Agents Chemother 36 (8): 1744–9. PMID 1416858. http://www.pubmedcentral.nih.gov/pagerender.fcgi?artid=192040. 
  4. ^ Heydorn, A.; Peterson, B. O.; Duus, J.; Bergmann, S.; Suhr-Jessen, T.; Nielson, J. Journal of Biological Chemistry. 2000, 275, 6201-6206.
  5. ^ Li, T-L.; Huang, F.; Haydock, S. F.; Mironenko, T.; Leadlay, P. F.; Spencer, J. B. Chemistry & Biology. 2004, 11, 107-119.
  6. ^ a b Kahne, D.; Leimkuhler, C.; Lu, W.; Walsh, C. Chem. Rev. 2005, 105, 425-448.
  7. ^ a b Hadatsch, B.; Butz, D.; Schmiederer, T.; Steudle, J.; Wohlleben, W.; Sussmuth, R.; Stegmann, E. Chemistry & Biology. 2007, 14, 1078-1089.
  8. ^ Kaplan, J.; Korty, B.D.; Axelsen, P.H., Loll; P. J. J. Med. Chem. 2001, 44, 1837-1840.
  9. ^ Ho, J-Y.; Huang, Y-T.; Wu, C-J.; Li, Y-S.; Tsai, M-D.; Li, T-L. J. Am. Chem. Soc. 2006, 128, 13694-13695.

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