6.2.5. 1 diketopiperazine
These substances are derived from cyclic dipeptide and are formed by dehydration of two amino acids, and the structural unit is epithiopiperazine-2,5-dione. Gliotoxin (127) comes from yellow-brown, gram-positive bacteria and has strong resistance to fungi and bacteria. Because of its toxicity to mammals, it has not been used in medical clinic. Gliotoxin is a selective immunosuppressant, and its biosynthesis is a cyclic dipeptide pathway of L- phenylalanine and L- serine (Kirby et al., 1980). When the S atom in sulfate radical is added to the colloid toxin, aromatic oxides may play an intermediate role in the synthesis process, forming R and R in Lvmu mold. Table 3 sulfur (128) comes from Trichoderma viride, and it is usually isolated from P.terlikowski.
Liewellyn (129) is essentially diketopiperazine, which is derived from the condensation reaction of two phenylalanine, although its structure is complicated (Stipanovic et al., 1994). Simple diketopiperazine (130) is derived from Trichoderma koningii (Huang et al., 1995a) and contains amide structure, which is between proline and leucine. They are also isolated from Chaetomium species. Verticillium wilt. And acremonium species. A colloid toxin analogue (13 1) was obtained from trichoderma longibrachiatum, which has inhibitory effect on Staphylococcus aureus, and its MIC = 13μ g/ml (Nakano et al., 1990). The chemical structural formula of these metabolites is shown in Figure 6. 12.
Fig. 6. 12 diketopiperazine, a metabolite derived from amino acids.
6.2.5.2 isonitrile derivatives
Metabolites with isocyanide functional groups have unique characteristics, and their C chain is connected with an N atom, and the general formula is RNC, which has volatile and foul smell and has long been concerned by chemists. Isocyanine obtained from Trichoderma has a typical five-membered ring structure and is oxidized by alkenyl, hydroxyl and epoxy groups (Chang, 2000). It is very difficult to study the structure of these metabolites, mainly because they are unstable and there is confusion in the description of their structures in many literatures. Some people have discussed the structural modification, and most of the structures mentioned in this chapter are modified. These substances mainly come from Trypanosoma HAMA, Trypanosoma harzianum, Trypanosoma corning, Trypanosoma polyspora and Trypanosoma viridis.
Xanthicillin was isolated from P.notatum in 1956, and a second metabolite, dermadin (132), was found after 10. It contains a functional group, and its antibacterial activity is described in the patent (Coats et al. The esterified derivative of dermadin (133) comes from T.hamatum(Brewer et al., 1979), followed by isocyanate F(65433 136) and spironolactone (137, 138). Lvmu (139) was also isolated from T.koningii, which is an inhibitor of melanin synthesis. The hemolymph of silkworm larvae was determined. It was found that the hemolymph could change from yellow to black under the conditions of ventilation and light, and the IC50 = 13. 1 μ g/ml. The IC50 of control kojic acid is 397 μ g/ml, and its structure has been verified by chemical methods and X- ray crystal analysis (Brewer et al., 1979).
Isocyanins A (140), B( 14 1), C and D( 142) came from Pteris uncinatus. The analysis confirmed that Isocyanin C was mycotoxin in Lvmu, and Isocyanin C was mycotoxin. It can inhibit the growth of Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Klebsiella pneumoniae, Candida albicans and Saccharomyces cerevisiae (IC50 range is 0.2 ~ 12.5 μ g/ml), and can be used as an animal feed additive (Fujiwara et al., Brewer et al., 1982).
Compounds 143 and 144 are hydroxyl-cyclopentyl isonitrile structures, and 14 1 is an isomer of MR304 A( 145) from Trichoderma harzianum (Lee et al., 1995b). MR304A can inhibit the melanin synthesis of Streptococcus bikini and melanoma cell B 16, and inhibit the tyrosinase activity of mushroom, but it has no antibacterial effect. Trichoderma harzianum MR566B( 146) and MR566A( 147) inhibited tyrosinase in mushrooms with IC50 of 47μM and 1.72 μ m, respectively, and inhibited melanoma cell B 16 with mic of 2.2 1 6, respectively.
Homozygotic proteins ⅰ and ⅱ and their derivatives (148 ~152) were found from Trichoderma koningii (Mukhopadhyay et al.,1996; Faull et al., 1994), these substances have inhibitory effect on rumen bacteria, and they are also found to be related to fertilization of Phytophthora. Oospores can also inhibit tyrosinase activity and melanin synthesis in mammals.
Trichoderma harzianum can produce cyclopentenone A ~ C (153 ~ 155), and its cytotoxicity to P388 is 0.2 1μg/mL and 1.25 respectively.
Many structurally related compounds from Trichoderma lack isocyanato groups, such as pentenoids A and B( 156, 157) produced by Trichoderma, and their three-dimensional structures are unknown. However, they are sensitive to interleukin-1-β invertase (ICE, caspase- 1). This enzyme is a cysteine protease, which converts the inactive precursor-interleukin-1 into the active form, which is related to the occurrence of inflammation (Matsumoto et al., 1999). The chemical structural formula of these metabolites is shown in Figure 6. 13.
Fig. 6. 13 Isocyanine derivatives derived from amino acids.
6.2.5.3 peptides and peptide alcohols.
There are two kinds of improved dipeptides, named Trichoderma cyclic peptides A and B( 158, 159), which are from marine Trichoderma viride. Trichoderma amide B has obvious cytotoxicity in vitro, and their inhibitory IC50 on human colon cancer cells HCT- 1 16. Trichoderma A has weak cytotoxicity to P388, A-549 and HL-60 (Garo et al., 2003; Liu et al, 2005a).
Peptide alcohols are peptide family substances, which contain a high proportion of unusual α, α-dimethylolbutyric acid (Aib), one containing amino alcohol C- terminal and one acylated N- terminal. The classification criteria of polypeptide subclasses are as follows: long-chain polypeptide (18 ~ 20 residues), short-chain polypeptide (1 1 ~ 16 residues) and liptopeptaibols (containing 7 or1residues).
The first substance in this family is Alamycin (160), which was isolated from Trichoderma viride (Brewer et al., 1987). Although its crystal was obtained and its structure was determined, later research found that Alami is actually a mixture, including at least 65438. Alamycin mainly has two configurations, one is glutamic acid at 18 position, and the other is glutamic acid, which is mainly resistant to G+ bacteria. Later, a large number of metabolites of this family were found from Trichoderma. Gliocladium. And other organisms (brukner et al., 1989), these substances are similar in structure, but show structural differences in a certain position or a few positions of amino acids, reflecting the characteristics of non-ribosomal metabolism mechanism. Alamycin has antibacterial activity against Staphylococcus. The inhibitory concentration of Enterococcus faecalis was 365438 0 μ g/ml, and that of Blastomyces dermatitis was 65438 000 μ g/ml. The oral LD50 = 80 mg/kg in mice also had a good inhibitory effect on tomato early blight, cucumber Fusarium wilt, watermelon Fusarium wilt and rice blast. Trichoderma and Alamycin were also found.
The secondary metabolites with 20 amino acid residues are structurally different from Alamycin. They are Suzuki Linz from Trichoderma viride (16 1) and Trichoderma polytrichum from Trichoderma polytrichum (New et al., 1996), paracaseins from Trichoderma reesei and Trichoderma fusiforme (Ritieni et al. Huang et al., 1995b).
The inhibitory concentrations of Ursolin on Bacillus subtilis and Aspergillus Niger were 100μg/mL and 100μg/mL, respectively, and it also had a control effect on animal coccidiosis. Feeding chickens with 0.005% ~ 0.0 1% of urokinase can prevent Eimeria tenella and Eimeria tenella infection (Katz et al., 1985). Uridine was also isolated from the 63C-I culture of Trichoderma viride strain, and SZ-A was obtained after crystallization. The structural identification by HPLC-ESI-MS showed that the main amino acid composition and sequence of the substance were consistent with the previously published data, except that it was acetylated at position 15, of which 2 1% was SZ-A4. The sequence is AC-Aib-Ala-Aib-Ala-Aib-Ala6-Gln-Aib-Lx9-Aib-Gly-Aib12-Aib-Pro-VX15-Aib-VX17-Gln-fol. The amino acid position changes are as follows: 6(Ala/Aib), 9(Vx/Lx), 12(Aib/Lx), 17(Aib/Vx) and 15 (Val/Ivana) (Krause et al., 2006). Paracelsins has high antibacterial activity against seven important forest pathogens, but it is cytotoxic to Artemia (Maddau et al., 2009).
The metabolites of marine trichoderma longibrachiatum were studied by ESI-MSn-IT and GC/EI-MS methods, and two main groups of peptide alcohols were obtained, namely long chain (20 amino acids) and short chain (1 1 amino acid). New short-chain antimicrobial peptides were also identified by this method, and 9 peptide compounds were found, 8 of which were new structural substances, namely Trichoderma AI-IV (AIB9-PRO 10 sequence) and Trichoderma BI-IV (VAL9-PRO 10 sequence). There are also previously discovered substances such as Pro6-Val7 and Val9-Pro 10 (Mohamed-Benkada et al., 2006).
Metabolites of Trichoderma koningii strain SMF2 can inhibit the growth of G+ bacteria and pathogenic fungi. Their structures were confirmed by liquid chromatography and mass spectrometry. It was found that these substances were mainly known polypeptides, including koninginins ⅵ, ⅶ and ⅷ. They had antibacterial activity in a wide pH range and temperature, but remained after autoclaving, and were insensitive to proteolytic enzymes. It was also found that koninginins (koninginins) were insensitive to proteolytic enzymes.
The substances containing 19 amino acid residues are: Trichoderma-9 species from Trichoderma harzianum (Bodo et al., 1985), Trichoderma (trichozianins = trichozianines) Ta and TB( 162). 163) inhibited the synthesis of β -glucan in the selectively permeable membrane of botrytis cinerea, but this effect was reversed after adding phosphatidylcholine, because the synthesis of β- 1, 3- glucan was also inhibited. Trikoningins from T.koningii has antibacterial activity against Staphylococcus aureus, but not against Escherichia coli (Auvin-Guette et al., 1993). Trichophyton comes from Trichophyton longum (rebuff at et al., 199 1), and Trichophyton isolated from Trichophyton scabra, Trichophyton hedgehog, Trichophyton stromatolite and Trichophyton spiraea has the function of preventing and treating apical blight of the genus Phytophthora.
The first secondary metabolite with 18 amino acid residues was trichotoxin from Trichoderma viride (Bruckner Hlimi et al., 1985), and the structures of trichokind and trichorzins isolated from Trichoderma harzianum were also confirmed. Trichoderma pa ⅱ, pav ⅲ (164, 165) can break the membrane of liposomes of different mollusks (Béven et al., 1998), and six Trichoderma pa (18). The inhibitory MIC of 8 species of leptospira, such as Mycoplasma acidophilus, Mycoplasma and Spiroplasma, is 3. 12 ~ 50μ m, and it is still active after the amino acid sequence changes, such as replacing Aib with Iva at position 4 and 7, and replacing Trpol with Pheol at C-terminal. Later, a new polypeptide with 18 amino acid residue was found, named Trichoderma, and a substance carrying free C-terminal valine was named Mucomycin (Degen Kolb et al., 2006).
Other short-chain peptides include trichoverins(Bruckner Trichoderma viride (Bruckner et al., 1992) and harzixin HA from Trichoderma harzianum (14-+04-residue) (Rebuffat et al., 12). Trikoningins KB (11-residue) from T.koningii (Auvin-Guette et al., 1993), Trichoderma Russell from T.harzianum (Wada et al., 65438). And trichorovins)(Wada et al., 1996). Trichoderma a (auvin-guette et al., 1992) from trichoderma longibrachiatum and Trichoderma -cenins (166) from Trichoderma viride are typical examples of lipopeptide alcohols (Fujita et al., different from others, Trichophyton I and II (167, 168) The inhibitory concentrations of trichopolyn, an N- terminal amino acid esterified with 2- amino -6- hydroxy -4- methyl -8- oxo, on Bacillus subtilis, Escherichia coli and Candida albicans were 6.25μg/mL, 65,438+000 μ g/ml and 6.25 μ g/ml, respectively (Ooka et al.
Moebin (169) is an insect repellent, and the inhibitory concentrations of Hypelcins (170) on Bacillus subtilis, Escherichia coli and Trichophyton rubrum are 25μg/mL and 170, respectively.
The mycoplasma of leptospira has no cell wall, DNA does not form nuclear structure, and it is Gram-positive, which is a pathogenic microorganism parasitic on animals and plants. These characteristics make leptospira an important target of antimicrobial peptide research. Prokaryotes and eukaryotes have different sensitivities to peptides, which may be due to the presence of sterols on eukaryotic plasma membranes. The cell membrane of leptospira, especially mycoplasma and spiroplasma, contains a lot of cholesterol, so the activity of polypeptide can't play a role. It can be inferred that the cell membrane of leptospira seems to be the target of non-specific ionophore of polypeptide, and polypeptide often comes from non-ribosome synthesis pathway. By studying the synthesis of cyclosporine (17 1), it is shown that exogenous amino acids can be absorbed to some extent to change the structure of metabolites. Directional synthesis has been confirmed in Trichoderma. For example, adding Aib, Glu or Arg to the culture medium of Trichoderma harzianum and trichoderma longibrachiatum can reduce the types of metabolites and sometimes produce new analogues (Leclerc et al., 200 1). These studies show that people can obtain the desired polypeptide by artificially intervening in the culture process. Because the metabolites of this family are similar in structure, only some substances are listed here, as shown in Figure 6. 14.