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Cyclic depsipeptides, grassypeptolides D and E and Ibu-epidemethoxylyngbyastatin 3, from a Red Sea Leptolyngbya cyanobacterium.

ABSTRACT: Two new grassypeptolides and a lyngbyastatin analogue, together with the known dolastatin 12, have been isolated from field collections and laboratory cultures of the marine cyanobacterium Leptolyngbya sp. collected from the SS Thistlegorm shipwreck in the Red Sea. The overall stereostructures of grassypeptolides D (1) and E (2) and Ibu-epidemethoxylyngbyastatin 3 (3) were determined by a combination of 1D and 2D NMR experiments, MS analysis, Marfey's methodology, and HPLC-MS. Compounds 1 and 2 contain 2-methyl-3-aminobutyric acid and 2-aminobutyric acid, while biosynthetically distinct 3 contains 3-amino-2-methylhexanoic acid and the ?-keto amino acid 4-amino-2,2-dimethyl-3-oxopentanoic acid (Ibu). Grassypeptolides D (1) and E (2) showed significant cytotoxicity to HeLa (IC?? = 335 and 192 nM, respectively) and mouse neuro-2a blastoma cells (IC?? = 599 and 407 nM, respectively), in contrast to Ibu-epidemethoxylyngbyastatin 3 (neuro-2a cells, IC?? > 10 ?M) and dolastatin 12 (neuro-2a cells, IC?? > 1 ?M).

SUBMITTER: Thornburg CC

PROVIDER: S-EPMC3170410 | biostudies-literature | 2011 Aug

REPOSITORIES: biostudies-literature

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Cyclic depsipeptides, grassypeptolides D and E and Ibu-epidemethoxylyngbyastatin 3, from a Red Sea Leptolyngbya cyanobacterium.

Thornburg Christopher C CC Thimmaiah Muralidhara M Shaala Lamiaa A LA Hau Andrew M AM Malmo Jay M JM Ishmael Jane E JE Youssef Diaa T A DT McPhail Kerry L KL

Journal of natural products 20110801 8

Two new grassypeptolides and a lyngbyastatin analogue, together with the known dolastatin 12, have been isolated from field collections and laboratory cultures of the marine cyanobacterium Leptolyngbya sp. collected from the SS Thistlegorm shipwreck in the Red Sea. The overall stereostructures of grassypeptolides D (1) and E (2) and Ibu-epidemethoxylyngbyastatin 3 (3) were determined by a combination of 1D and 2D NMR experiments, MS analysis, Marfey's methodology, and HPLC-MS. Compounds 1 and 2 ...[more]

PMID: 21806012

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Project description:BACKGROUND:Cyanobacteria are recognized as the primordial organisms to grace the earth with molecular oxygen ~3.5 billion years ago as a result of their oxygenic photosynthesis. This laid a selection pressure for the evolution of antioxidative defense mechanisms to alleviate the toxic effect of active oxygen species (AOS) in cyanobacteria. Superoxide dismutases (SODs) are metalloenzymes that are the first arsenal in defense mechanism against oxidative stress followed by an array of antioxidative system. Unlike other living organisms, cyanobacteria possess multiple isoforms of SOD. Hence, an attempt was made to demonstrate the oxidative stress tolerance ability of marine cyanobacterium, Leptolyngbya valderiana BDU 20041 and to PCR amplify and sequence the SOD gene, the central enzyme for alleviating stress. RESULT:L. valderiana BDU 20041, a filamentous, non-heterocystous marine cyanobacterium showed tolerance to the tested dye (C.I. Acid Black 1) which is evident by increased in biomass (i.e.) chlorophyll a. The other noticeable change was the total ROS production by culture dosed with dye compared to the control cultures. This prolonged incubation showed sustenance, implying that cyanobacteria maintain their antioxidant levels. The third significant feature was a two-fold increase in SOD activity of dye treated L. valderiana BDU20041 suggesting the role of SOD in alleviating oxidative stress via Asada-Halliwell pathway. Hence, the organism was PCR amplified for SOD gene resulting in an amplicon of 550 bp. The sequence analysis illustrated the presence of first three residues involved in motif; active site residues at H4, 58 and D141 along with highly conserved Mn specific residues. The isolated gene shared 63.8% homology with MnSOD of bacteria confirmed it as Mn isoform. This is the hitherto report on SOD gene from marine cyanobacterium, L. valderiana BDU20041 of Indian subcontinent. CONCLUSION:Generation of Reactive Oxygen Species (ROS) coupled with induction of SOD by marine cyanobacterium, L. valderiana BDU20041 was responsible for alleviating stress caused by an azo dye, C. I. Acid Black 1. The partial SOD gene has been sequenced and based on the active site, motif and metal specific residues; it has been identified as Mn metalloform.

Dataset Information

Cyclic depsipeptides, grassypeptolides D and E and Ibu-epidemethoxylyngbyastatin 3, from a Red Sea Leptolyngbya cyanobacterium.

Publications

Cyclic depsipeptides, grassypeptolides D and E and Ibu-epidemethoxylyngbyastatin 3, from a Red Sea Leptolyngbya cyanobacterium.

Similar Datasets

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