Dihydrotentoxin: A precursor of tentoxin or its degradation product?

Liebermann, Bernd; Ihn, W.

doi:10.1002/jobm.3620280109

Cited by 11 publications

(4 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Although the biothe toxin on the CFa. The HPLC technique that we used, the synthesis of radiolabeled tentoxin is possible [26], the accessiHummel and Dreyer method, suggested the presence of a ble specific activity is generally too low for a reliable determisecond low-affinity binding site (with an estimated nation of tentoxin binding to CF1 [7]. The total organic K~ =6.3 × 103 M-l).…”

Section: Resultsmentioning

confidence: 99%

Tentoxin has at least two binding sites on CF₁ and ϵ‐depleted CF₁ ATPases isolated from spinach chloroplast

et al. 1996

View full text Add to dashboard Cite

A new procedure for synthesis of 14C-labeled tentoxin recovery of the ATPase activity [10]. Interestingly, a tightly [14C-MePhe[(Z)A]3-tentoxin], with a high specific activity, is coupled proton transport is preserved in the partially reactidescribed. Binding experiments with CFt or CFt-E isolated from vated CF0-F1 by high concentrations of tentoxin [10], and the spinach chloroplast have been carried out using equilibrium interaction between the nucleotide binding sites, which plays a dialysis technique. The results show the presence of two classes of important role in the functioning of this complex, is severely binding sites. The association constants of the two major binding altered [11,12]. sites were derived from non-linear fitting of the binding curves.The precise binding site for tentoxin on CF1 has not been At 4°C, the first binding site has a value of K,I = 8.2 × 105 M -I yet identified. There is some evidence that tentoxin binds to in CF1 and 8.7 × 105 M -1 in CF1-E, while the second binding site the [3-subunit [3,11] although amino acids involved in the has lower affinity with K,2 = 1.5 x 104 M -1 in CF1 and 2.3 x 103 binding are still a matter of controversy [5,13]. A binding M -t in CFI-a.site located on the a-subunit or at an interface between the Key words." H+-ATPase; Chloroplast ATP synthase; subunits c~ and [3 is also a possibility [7,14]. In addition, the 14C-Labelled tentoxin; Cyclic tetrapeptide; Equilibrium binding of the 7-subunit to the ¢xl3-complex is necessary for dialysis; Spinacia oleracea L. sized by new methods, we present here an investigation of H+-ATPase. This enzyme couples the downhill proton flow tentoxin binding on spinach CF1 and CFI-~, which reveals generated by the photosynthetic redox chain with ATP synat least two types of binding sites with different affinities. thesis. Numerous studies have shown that tentoxin tightly binds to the soluble F1 moiety of the enzyme [2,4], but very little is 2. Materials and methods known about the mode of action of the toxin. The extrinsic part of chloroplastic ATP synthase, CF1, is a multi-subunit 14C-Labelled tentoxinenzyme (stoichiometry c~3133T6a) with latent ATPase activity.BocMeAla-Leu-AZPhe-GlyOMe (1) was obtained in homogeneous Removal of the E-subunit and/or chemical reduction of the phase using the synthesis scheme recently described [16] skipping the lone disulfide bond of the enzyme located on the 7-subunit methylation step of the dehydrophenylalanyl residue (AZPhe). HPLC activates ATPase activity [5]. For sensitive plants, tentoxin Rt= 23.2 min on C18 Protein&Peptide VYDAC analytical column (MeOH/H20 60/40 v/v, 0.6 ml rain-l). Using [14C]methyl iodide binding inhibits the CF1-ATPase activity at low concentration freshly synthesized [17] from [14C]methanol produced from 14CO2 (10 -8 M) [2,4,6,7] and stimulates it at a concentration of 10 -5 (specific activity 55 mCi/mmol) [18,19], selective radioactive methyla-M and higher [6][7][8][9]. The activation phenomenon also exists in tion was then performed according to [...

show abstract

Section: Resultsmentioning

confidence: 99%

Tentoxin has at least two binding sites on CF₁ and ϵ‐depleted CF₁ ATPases isolated from spinach chloroplast

et al. 1996

View full text Add to dashboard Cite

show abstract

“…Little is known concerning its biosynthesis, and it has yet to be determined whether tentoxin synthesis proceeds through thioester template typical of many cyclic peptides or through an as yet undiscovered mechanism. Data from our lab (5) and that of Iiebermann and Ihn (12) indicate a mechanism different from the thioester pathway, however, this pathway has not been ruled out. Strain selection, media composition and fermentation parameters have not yielded significantly higher production of the toxin.…”

Section: Figure 1 Structure Of Tentoxin [Cyclo(n-methylalanyl-leucylmentioning

confidence: 88%

“…The use of tentoxin as a herbicide has been hampered by its relatively low biosynthetic yield by even selected high producing strains of Alternaria (1,2,5,12), even with its potent biological activity in the micromolar range. This is probably the major obstacle to the development of tentoxin; because of their generally potent activity and consequently low biosynthesis this promises to be problematic with other, as yet undiscovered, microbial toxins as pesticides.…”

Section: Figure 1 Structure Of Tentoxin [Cyclo(n-methylalanyl-leucylmentioning

confidence: 99%

Biorational Control of Weeds and Fungi with Peptides

Lax

Bland

Shepherd

1993

Natural and Engineered Pest Management Agents

View full text Add to dashboard Cite

Tentoxin is a cyclic tetrapeptide produced by the fungus Alternaria alternata that disrupts chloroplast development in most of the major weed species in soybean and johnsongrass in corn while having no effect on either of these crop species. The major impediment to the development of tentoxin as a herbicide is its limited availability because of low biosynthetic yields. Iturins are a family of cyclic octapeptides having a unique β-amino acid, iturinic acid, incorporated into the peptide backbone. Iturins have a broad antifungal activity, but low biosynthetic yields may limit their commercialization. Chemical synthesis of both molecules is possible and the production of analogues has led to meaningful structure/activity relationships. To date no analog has provided greater activity or specificity than the parent molecule for either of the two agents. Molecular genetic manipulation is considered the best strategy for the increase in production of both of these compounds for cost effective synthesis. Success of cloning of the biosynthetic genes may determine the eventual deployment of these biorational pesticides.The cost of pest control in agriculture is staggering; direct costs of pesticides are estimated to be at least $20 billion annually, with unestimated indirect costs making the exact amount impossible to accurately state. Recent popular concern for the environment and legislation toward banning some of the more traditional pesticide compounds has led to the development of new strategies for the control of pests which include microbes as biological control organisms and the use of the biorational approach in which natural products provide a basis for the This chapter not subject to U.S.

show abstract

“…mali, A. citri, A. porri, A. solani, A. bataticola, A. cucumerina, A. alternata, A. longipes, and A.japonica (Suemitsu et aI., 1990, I 992a). In addition to tentoxin, two structurally related compounds, isotentoxin and dihydrotentoxin (DHT) have also been isolated from Alternaria cultures (Kono et aI., 1986b;Liebermann and Ihn, 1988;Liebermann et aI., 1996). Structurally, the phytotoxin is a cyclic tetrapeptide in a sequence of cyclo-(L-Ieucyl-N-methyl-dehydrophenylalanyl-glycyl-N-methyl-L-alanyl) (Meyeret aI.,1974): Like many bioactive cyclic peptides, tentoxin appears to be synthesized by a nonribosomal peptide synthesis mechanism.…”

Section: F Tentoxinmentioning

confidence: 99%

Phytotoxins and Plant Pathogenesis

Huang

2001

Plant Pathogenesis and Resistance

View full text Add to dashboard Cite

Dihydrotentoxin: A precursor of tentoxin or its degradation product?

Cited by 11 publications

References 21 publications

Tentoxin has at least two binding sites on CF₁ and ϵ‐depleted CF₁ ATPases isolated from spinach chloroplast

Tentoxin has at least two binding sites on CF₁ and ϵ‐depleted CF₁ ATPases isolated from spinach chloroplast

Biorational Control of Weeds and Fungi with Peptides

Phytotoxins and Plant Pathogenesis

Contact Info

Product

Resources

About

Dihydrotentoxin: A precursor of tentoxin or its degradation product?

Cited by 11 publications

References 21 publications

Tentoxin has at least two binding sites on CF1 and ϵ‐depleted CF1 ATPases isolated from spinach chloroplast

Tentoxin has at least two binding sites on CF1 and ϵ‐depleted CF1 ATPases isolated from spinach chloroplast

Biorational Control of Weeds and Fungi with Peptides

Phytotoxins and Plant Pathogenesis

Contact Info

Product

Resources

About

Tentoxin has at least two binding sites on CF₁ and ϵ‐depleted CF₁ ATPases isolated from spinach chloroplast

Tentoxin has at least two binding sites on CF₁ and ϵ‐depleted CF₁ ATPases isolated from spinach chloroplast