PMID- 23457475
OWN - NLM
STAT- MEDLINE
DCOM- 20130826
LR  - 20211021
IS  - 1932-6203 (Electronic)
IS  - 1932-6203 (Linking)
VI  - 8
IP  - 2
DP  - 2013
TI  - In silico analysis of putative paralytic shellfish poisoning toxins export 
      proteins in cyanobacteria.
PG  - e55664
LID - 10.1371/journal.pone.0055664 [doi]
LID - e55664
AB  - 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 L(398)XGLQD(403) (SxtM) and L(390)VGLRD(395) (SxtF) 
      in toxin recognition.
FAU - Soto-Liebe, Katia
AU  - Soto-Liebe K
AD  - Pontificia Universidad Catolica de Chile, Santiago, Chile.
FAU - Lopez-Cortes, Xaviera A
AU  - Lopez-Cortes XA
FAU - Fuentes-Valdes, Juan Jose
AU  - Fuentes-Valdes JJ
FAU - Stucken, Karina
AU  - Stucken K
FAU - Gonzalez-Nilo, Fernando
AU  - Gonzalez-Nilo F
FAU - Vasquez, Monica
AU  - Vasquez M
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20130215
PL  - United States
TA  - PLoS One
JT  - PloS one
JID - 101285081
RN  - 0 (Bacterial Proteins)
RN  - 0 (Marine Toxins)
RN  - 0 (Membrane Transport Proteins)
RN  - 35523-89-8 (Saxitoxin)
SB  - IM
EIN - PLoS One. 2013;8(9). doi:10.1371/annotation/98980683-2c5f-4c7f-b2ab-345d558bf9b7
MH  - Bacterial Proteins/chemistry/genetics/*metabolism
MH  - Biological Transport, Active
MH  - Computer Simulation
MH  - Cylindrospermopsis/chemistry/genetics/*metabolism
MH  - Marine Toxins/chemistry/genetics/*metabolism
MH  - Membrane Transport Proteins/chemistry/genetics/*metabolism
MH  - Models, Molecular
MH  - Multigene Family
MH  - Phylogeny
MH  - Protein Conformation
MH  - Saxitoxin/analogs & derivatives/genetics/metabolism
PMC - PMC3574068
COIS- Competing Interests: The authors have declared that no competing interests exist.
EDAT- 2013/03/05 06:00
MHDA- 2013/08/27 06:00
PMCR- 2013/02/15
CRDT- 2013/03/05 06:00
PHST- 2012/09/21 00:00 [received]
PHST- 2012/12/29 00:00 [accepted]
PHST- 2013/03/05 06:00 [entrez]
PHST- 2013/03/05 06:00 [pubmed]
PHST- 2013/08/27 06:00 [medline]
PHST- 2013/02/15 00:00 [pmc-release]
AID - PONE-D-12-28971 [pii]
AID - 10.1371/journal.pone.0055664 [doi]
PST - ppublish
SO  - PLoS One. 2013;8(2):e55664. doi: 10.1371/journal.pone.0055664. Epub 2013 Feb 15.