In Silico Analysis of Putative Paralytic Shellfish Poisoning Toxins Export Proteins in Cyanobacteria

Soto-Liebe, Katia; López-Cortés, Xaviera A.; Fuentes-Valdes, Juan José; Stucken, Karina; Gonzalez-Nilo, Fernando; Vásquez, Mónica
February 2013
PLoS ONE;Feb2013, Vol. 8 Issue 2, p1
Academic Journal
Paralytic shellfish poisoning toxins (PSTs) are a family of more than 30 natural alkaloids synthesized by dinoflagellates and cyanobacteria whose toxicity in animals is mediated by voltage-gated Na+ channel blocking. The export of PST analogues may be through SxtF and SxtM, two putative MATE (multidrug and toxic compound extrusion) family transporters encoded in PSTs biosynthetic gene cluster (sxt). sxtM is present in every sxt cluster analyzed; however, sxtF is only present in the Cylindrospermopsis-Raphidiopsis clade. These transporters are energetically coupled with an electrochemical gradient of proton (H+) or sodium (Na+) ions across membranes. Because the functional role of PSTs remains unknown and methods for genetic manipulation in PST-producing organisms have not yet been developed, protein structure analyses will allow us to understand their function. By analyzing the sxt cluster of eight PST-producing cyanobacteria, we found no correlation between the presence of sxtF or sxtM and a specific PSTs profile. Phylogenetic analyses of SxtF/M showed a high conservation of SxtF in the Cylindrospermopsis-Raphidiopsis clade, suggesting conserved substrate affinity. Two domains involved in Na+ and drug recognition from NorM proteins (MATE family) of Vibrio parahaemolyticus and V. cholerae are present in SxtF/M. The Na+ recognition domain was conserved in both SxtF/M, indicating that Na+ can maintain the role as a cation anti-transporter. Consensus motifs for toxin binding differed between SxtF and SxtM implying differential substrate binding. Through protein modeling and docking analysis, we found that there is no marked affinity between the recognition domain and a specific PST analogue. This agrees with our previous results of PST export in R. brookii D9, where we observed that the response to Na+ incubation was similar to different analogues. These results reassert the hypothesis regarding the involvement of Na+ in toxin export, as well as the motifs L398XGLQD403 (SxtM) and L390VGLRD395 (SxtF) in toxin recognition.


Related Articles

  • Neurotoxic Alkaloids: Saxitoxin and Its Analogs. Wiese, Maria; D'Agostino, Paul M.; Mihali, Troco K.; Moffitt, Michelle C.; Neilan, Brett A. // Marine Drugs;Jul2010, Vol. 8 Issue 7, p2185 

    Saxitoxin (STX) and its 57 analogs are a broad group of natural neurotoxic alkaloids, commonly known as the paralytic shellfish toxins (PSTs). PSTs are the causative agents of paralytic shellfish poisoning (PSP) and are mostly associated with marine dinoflagellates (eukaryotes) and freshwater...

  • Evolution and Distribution of Saxitoxin Biosynthesis in Dinoflagellates. Orr, Russell J. S.; Stüken, Anke; Murray, Shauna A.; Jakobsen, Kjetill S. // Marine Drugs;Aug2013, Vol. 11 Issue 8, p2814 

    Numerous species of marine dinoflagellates synthesize the potent environmental neurotoxic alkaloid, saxitoxin, the agent of the human illness, paralytic shellfish poisoning. In addition, certain freshwater species of cyanobacteria also synthesize the same toxic compound, with the biosynthetic...

  • Paralytic toxins in Taiwanese crab Xanthias lividus. TSAI, Yung-Hsiang; HO, Ping-Ho; JENG, Sen-Shyong; HWANG, Deng-Fwu // Fisheries Science;Jun2002, Vol. 68 Issue 3, p659 

    Paralytic toxicity was detected by tetrodotoxin (TTX) bioassay in four and five specimens of new toxic xanthid crab Xanthia lividus collected from Lanyu, south-east Taiwan in April 1999 and Hsiaoliuchiu south-west Taiwan in November 1999, respectively. The average toxicity of crab specimens...

  • Purification and characterization of sulfotransferase specific to O-22 of 11-hydroxy saxitoxin from the toxic dinoflagellate Gymnodinium catenatum (dinophyceae). YOSHIDA, Takashi; SAKO, Yoshihiko; UCHIDA, Aritsune; KAKUTANI, Tomonori; ARAKAWA, Osamu; NOGUCHI, Tamao; ISHIDA, Yuzaburo // Fisheries Science;Jun2002, Vol. 68 Issue 3, p634 

    A novel sulfotransferase (O-ST), which transferred the sulfate group of 3′-phosphoadenosine 5′-phosphosulfate (PAPS) to O-22 of 11-α,β-hydroxy saxitoxin (STX) and produced GTX2 + 3, was purified to homogeneity from the cytosolic fraction of clonal-axenic vegetative cells of the...

  • Seattle and NW Washington SPOTLIGHTS.  // Skanner (Seattle, WA & Portland, OR Combined Edition);8/5/2015, Vol. 37 Issue 44, p10 

    The article offers news briefs for Seattle and North West Washington for 2015 including hosting of an event on Social Security, Medicare, and Medicaid by Social Security Works Washington coalition and detection of unsafe levels of Paralytic Shellfish Poison in shellfish on Vashon-Maury Island.

  • Paralytic Shellfish Poisoning -- Southeast Alaska, May-June 2011. McLaughlin, Joseph B.; Fearey, Donna A.; Esposito, Tari A.; Porter, Kimberly A. // MMWR: Morbidity & Mortality Weekly Report;11/18/2011, Vol. 60 Issue 45, p1554 

    The article reports on cases of paralytic shellfish poisoning (PSP) in southeast Alaska observed by the Section of Epidemiology (SOE) of the Alaska Division of Public Health. A probable case of PSP was defined as a compatible illness including paresthesias in a person shortly after consumption...

  • Ciguatera poisoning. Tatnall, F.M.; Smith, H.G.; Welshy, P.D.; Turnbull, P.C.B. // British Medical Journal;10/4/1980, Vol. 281 Issue 6245, p948 

    Presents a case of ciguatera poisoning. Clinical feature of the patient; Distinction between ciguatera poisoning and paralytic shellfish poisoning; Symptoms of the poisoning.

  • Evaluation of mouse bioassay results in an inter-laboratory comparison for paralytic shellfish poisoning toxins. Cao, Jijuan; Zheng, Jiang; Yu, Bing; Wang, Qiuyan; Xu, Junyi; Li, Aifeng // Chinese Journal of Oceanology & Limnology;Jul2011, Vol. 29 Issue 4, p912 

    n inter-laboratory comparison of the AOAC mouse bioassay for paralytic shellfish poisoning (PSP) toxicity in shellfish was carried out among 25 Chinese laboratories to examine the overall performance for PSP testing in China, and to analyze the main factors affecting the performance of this...

  • Preface to the special issue on eutrophication and HABs: the GEOHAB approach. Glibert, P.; Zhou, Mingjiang; Zhu, Mingyuan; Burford, M. // Chinese Journal of Oceanology & Limnology;Jul2011, Vol. 29 Issue 4, p719 

    An introduction is presented in which the editor discusses various reports within the issue on topics including the interaction between Microcystis and Daphnia magna, paralytic shellfish poisoning, and harmful algal blooms.


Read the Article


Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics