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1znu

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Revision as of 11:48, 25 December 2014

Structure of cyclotide Kalata B1 in DPC micelles solution

Structural highlights

1znu is a 1 chain structure with sequence from Oldenlandia affinis. Full experimental information is available from OCA. For a guided tour on the structure components use FirstGlance.
Related:	1kal, 1jjz, 1nb1
Resources:	FirstGlance, OCA, RCSB, PDBsum

Function

[KAB1_OLDAF] Probably participates in a plant defense mechanism. Has antibiotic activity. Has a diuretic effect. Has a uterotonic effect in humans. Active against the Gram-positive S.aureus with a minimum inhibition concentration of approximately 0.2 microM. Relatively ineffective against Gram-negative bacteria such as E.coli and P.aeruginosa. Inhibitory effect on the growth and development of larvae from H.punctigera. The unmodified form has hemolytic activity, the oxidized form lacks hemolytic activity. If the protein is linearized, hemolytic activity is lost.^[1] ^[2]

Publication Abstract from PubMed

Cyclotides are a family of bioactive plant peptides that are characterized by a circular protein backbone and three conserved tightly packed disulfide bonds. The antimicrobial and hemolytic properties of cyclotides, along with the relative hydrophobicity of the peptides, point to the biological membrane as a target for cyclotides. To assess the membrane-induced conformation and orientation of cyclotides, the interaction of the Mobius cyclotide, kalata B1, from the African perennial plant Oldenlandia affinis, with dodecylphosphocholine micelles was studied using NMR spectroscopy. Under conditions where the cyclotide formed a well-defined complex with micelles, the spatial structure of kalata B1 was calculated from NOE and J couplings data, and the model for the peptide-micelle complex was built using 5- and 16-doxylstearate relaxation probes. The binding of divalent cations to the peptide-micelle complex was quantified by Mn2+ titration. The results show that the peptide binds to the micelle surface, with relatively high affinity, via two hydrophobic loops (loop 5, Trp19-Val21; and loop6, Leu27-Val29). The charged residues (Glu3 and Arg24), along with the cation-binding site (near Glu3) are segregated on the other side of the molecule and in contact with polar head groups of detergent. The spatial structure of kalata B1 is only slightly changed during incorporation into micelles and represents a distorted triple-stranded beta-sheet cross-linked by a cystine knot. Detailed structural analysis and comparison with other knottins revealed structural conservation of the two-disulfide motif in cyclic and acyclic peptides. The results thus obtained provide the first model for interaction of cyclotides with membranes and permit consideration of the cyclotides as membrane-active cationic antimicrobial peptides.

Conformation and mode of membrane interaction in cyclotides. Spatial structure of kalata B1 bound to a dodecylphosphocholine micelle.,Shenkarev ZO, Nadezhdin KD, Sobol VA, Sobol AG, Skjeldal L, Arseniev AS FEBS J. 2006 Jun;273(12):2658-72. PMID:16817894^[3]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

↑ Plan MR, Goransson U, Clark RJ, Daly NL, Colgrave ML, Craik DJ. The cyclotide fingerprint in oldenlandia affinis: elucidation of chemically modified, linear and novel macrocyclic peptides. Chembiochem. 2007 Jun 18;8(9):1001-11. PMID:17534989 doi:http://dx.doi.org/10.1002/cbic.200700097
↑ Barry DG, Daly NL, Clark RJ, Sando L, Craik DJ. Linearization of a naturally occurring circular protein maintains structure but eliminates hemolytic activity. Biochemistry. 2003 Jun 10;42(22):6688-95. PMID:12779323 doi:http://dx.doi.org/10.1021/bi027323n
↑ Shenkarev ZO, Nadezhdin KD, Sobol VA, Sobol AG, Skjeldal L, Arseniev AS. Conformation and mode of membrane interaction in cyclotides. Spatial structure of kalata B1 bound to a dodecylphosphocholine micelle. FEBS J. 2006 Jun;273(12):2658-72. PMID:16817894 doi:EJB5282

1 Structural highlights
2 Function
3 Publication Abstract from PubMed
4 References

Proteopedia Page Contributors and Editors (what is this?)

OCA

Retrieved from "http://52.214.119.220/wiki/index.php/1znu"

@@ Line 6: / Line 6: @@
 <tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1znu FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1znu OCA], [http://www.rcsb.org/pdb/explore.do?structureId=1znu RCSB], [http://www.ebi.ac.uk/pdbsum/1znu PDBsum]</span></td></tr>
 </table>
+== Function ==
+[[http://www.uniprot.org/uniprot/KAB1_OLDAF KAB1_OLDAF]] Probably participates in a plant defense mechanism. Has antibiotic activity. Has a diuretic effect. Has a uterotonic effect in humans. Active against the Gram-positive S.aureus with a minimum inhibition concentration of approximately 0.2 microM. Relatively ineffective against Gram-negative bacteria such as E.coli and P.aeruginosa. Inhibitory effect on the growth and development of larvae from H.punctigera. The unmodified form has hemolytic activity, the oxidized form lacks hemolytic activity. If the protein is linearized, hemolytic activity is lost.<ref>PMID:17534989</ref> <ref>PMID:12779323</ref>
 <div style="background-color:#fffaf0;">
 == Publication Abstract from PubMed ==

1znu

From Proteopedia

Revision as of 11:48, 25 December 2014

Structure of cyclotide Kalata B1 in DPC micelles solution

Structural highlights

Function

Publication Abstract from PubMed

References

Contents

Proteopedia Page Contributors and Editors (what is this?)

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