Peptides ascidian

Donia, M.S., Hathaway, B.J., Sudek, S. et al. (2006) Natural combinatorial peptide libraries in cyanobacterial symbionts of marine ascidians. Nature Chemical Biology, 2, 729. 

That the Indo-Pacific (Fig. 7.1.II) is an area of high natural product diversity was first revealed by the studies carried out in the 1970 s at the Roche Research Institute on the Great Barrier Reef (Baker 1980). Studies worldwide have since confirmed this richness, unsurpassed by any other area, either in the sea or on land. The variety of small peptides from the Indo-Pacific is impressive, characterized, particularly with the ascidians, by the condensation of the cysteine NH2 and SH groups with the COOH group of an adjacent amino acid. Thiazole and thiazoline rings are formed, which alternate with the normal peptide bonds formed by the other amino acids (Chart 7.2.P1-3). Correspondingly, threonine forms methyloxazoline moieties (Chart 7.2. A, 7.2.P1,7.2.P2). These condensations inqiose a drastic conformational bias to peptides (Abbenante 1996). 

Carroll, A.R. Coll, J.C. Bourne, D.J. Macleod, J.K. Zabriskie, T.M. Ireland, C.M. Bowden, B.F. (1996) Patellins 1-6 and trunkamide A novel cyclic hexa-, hepta- and octa-peptides from colonial ascidians, Lissoclinum sp. Aust. J. Chem., 49, 659-67. 

Swersey, J.C. Ireland, C.M. Cornell, L.M. Peterson, R.W. (1994) Eusynstyelamide, a highly modified dimer peptide from the ascidian Eusynstyela misakiensis. J. Nat. Prod., 57, 842-5. 

Ascidiacyclamide (14), a cytotoxic, cyclic peptide, was isolated from an unidentified species of ascidian [40], The absolute configuration was determined and the structure confirmed by total synthesis [41]. An X-ray crystal structure was carried out [42] and further X-ray crystallographic studies determined the conformation of the molecule in the solid- and solution-states [43]. 

The virenamides A-C (180-182), thiazole-containing cytotoxic linear peptides, were isolated from the colonial ascidian Diplosoma virens collected on the Great Barrier Reef, Australia. Their structures were... 

One of the more interesting and structurally complex indole-containing peptides is the previously described diazonamide (A and B) from the ascidian Diazona... 

Taylor SW, Craig AG, Fischer WH, Park M, Lehrer RI (2000) Styelin D, an Extensively Modified Antimicrobial Peptide from Ascidian Hemocytes. J Biol Chem 275 38417... 

Carroll, A. R., Feng, Y., Bowden, B. F., and Coll, J. C., Studies of Australian ascidians. 5. Virenamides A-C, new cytotoxic linear peptides from the colonial didemnid ascidian Diplosoma virens, J. Org. Chem., 61, 4059, 1996. 

Ascidians are marine filter feeders with a rich natural products chemistry that five commonly associated with symbiotic bacteria (88, 89, 109). A well-studied symbiosis consists of photosynthetic Prochloron spp. cyanobacteria that occur in ascidians of the family Didemnidae (110). Prochloron spp. also can be found in bacterial mat structures of stromatoliths (111) but so far have not been detected outside of such structured environments. From didemnid ascidians, numerous cytotoxic cyclic peptides of the patellamide group (Fig. 5) were isolated (109, 112, 113). Mechanical separation of the Prochloron sp. symbiont from its host Lissoclinum patella and subsequent genome sequencing revealed a set of biosynthetic genes that after transfer into E. coli enabled this bacterium to produce two different patellamides (114). The genes also were identified in an independent study by screening a library of Prochloron sp. DNA... 

Degnan BM, Hawkins CJ, Lavin ME, McCaffrey EJ, Parry DL, van den Brenk AL, Watters DJ. New cyclic peptides with cytotoxic activity from the ascidian Lissoclinumpatella. J. Med. 129. Chem. 1989 32 1349-1354. 

The text of this was modified from the PhD thesis of L. A. Morris, Studies on the Cu(II) and Zn(II) binding properties of cyclic peptides from the ascidian Lissoclinum patella, Aberdeen University, Aberdeen, 1999. 

Study of the ascidian L. patella (order Enterogona, family Didemnidae) yielded two new closely related cyclic peptide alkaloids namely lissoclinamide 9 389 and lissoclinamide 10 390 <2000T8345>. Their structures were determined by a combination of 2-D NMR, selective 1-D TOCSY, MS, and series-wound electrospray ionization (ESI)-MS (MSn) techniques, and the assignment of absolute stereochemistry was achieved by the hydrolysis of lissoclinamides followed by chiral thin layer chromatography. In the case of lissoclinamide 9, 389, NOE-restrained molecular dynamics studies were also performed confirming the proposed stereochemistry. 

Further four new cyclic thiazole peptides, patellamide G (404, a novel immunosuppressant), ulithiacyclamides E 405, F 406 and G 407, were isolated from the ascidian L. patella <1998JNP1547, 1998JA12237>. 

Much interest and research over the past 15 or so years has been directed towards ascidian metabolites because of the high incidence of pharmacological activity that they display. Few comprehensive reviews exist on the topic the only general ones being those produced by Davidson in 1993 [1,2] and the Marine Natural Product literature reviews by Faulkner which always contain a section on tunicate metabolites [3-13]. Although a number of non-nitrogenous metabolites have been isolated from the tunicates, the majority of compoimds isolated have been derived from amino acids. In particular, the two most commonly encountered classes are cyclic peptides and polycyclic aromatic alkaloids. 

Although the division between the peptides and other nitrogen-containing metabolites derived from ascidians is not a clear cut one, the literature published on the non-peptidic, tunicate-derived alkaloids which contain aromatic (often in combination with heteroaromatic) rings has been summarised. The few linear peptides (which contain aromatic amino acid residues) have also been included because of their apparent structural... 

The Other modified linear peptides reported are virenamides A-E (43-47) from the didemnid ascidian Diplosoma virens [40,41]. Strictly speaking, these metabolites are apparently derived from 4 amino acids so should be regarded as tetrapeptides, but are more conveniently regarded as carboxy-protected tripeptides (where the carboxyl group has been... 

The bioactIve secondary metabolites from several marine sources, sponges and tunica-tes (Kobayashl/lshibashi), sea plumes (Katz/Adamczeski) and ascidians (Bowdem) cover a broad range of different chemical structures, terpenoids, unsaturated fatty acids, steroids, alkaloids, cyclic peptides and polysaccharides. 

The sperm chemoattractants in nonmammalian species vary to a large extent. Some examples are shown in Table 2. So far, most sperm chemoattractants that have been identified in animals are peptides or low-molecular-weight proteins (l-20kDa), which are heat stable and sensitive to proteases [35, 102]. Exceptions to the rule are the sperm chemoattractants of corals—lipid-hke substances of 140-250 Da [30], and the chemoattractants of the ascidians Ciona—a sulfated steroid [187, 189]. In plants such as ferns, the partially ionized form of malic acid and a large variety of unsaturated four-carbon cis-dicarbojg lic acids are sperm chemoattractants [35], In algae, low-molecular-weight... 

Hamamoto Y, Endo M, Nakagawa M, Nakanishi T Mizukawa K 1983 A new cyclic peptide, ascidiacylamide, isolated from Ascidian. J Chem Soc Chem Commun 323-324... 

Figure 8.1 Cyclic peptides from (a) sponges, (b) red algae, (c) ascidians, (d) sea hares, (e) bacteria, (f) fungi, and (g) plants.

Hamamoto, Y., M. Endo, M. Nakagawa, T. Nakanishi, and K. Mizukawa A New Cyclic Peptide, Ascidiacyclamide, Isolated from Ascidian. J. Chem. Soc., Chem. Commun. 1983, 323. 

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