1TKQ

SOLUTION STRUCTURE OF A LINKED UNSYMMETRIC GRAMICIDIN IN A MEMBRANE-ISOELECTRICAL SOLVENTS MIXTURE IN THE PRESENCE OF CsCl

Summary for 1TKQ

• Entry DOI: 10.2210/pdb1tkq/pdb
• Related: 1AL4 1ALX 1ALZ 1AV2 1BDW 1C4D 1GMK 1GRM 1JNO 1JO3 1JO4 1KQE 1MAG 1MIC 1NG8 1NRM 1NRU 1NT5 1NT6 1TK2 1W5U 2IZQ 2XDC 3L8L
• Related PRD ID: PRD_000155
• Descriptor: MINI-GRAMICIDIN A, GRAMICIDIN A, SUCCINIC ACID (3 entities in total)
• Functional Keywords: gramicidin, antifungal, antibacterial, antibiotic, membrane ion channel, linear gramicidin
• Biological source: BREVIBACILLUS BREVIS; More
• Total number of polymer chains: 2
• Total formula weight: 3400.10

Authors

Xie, X.,Al-Momani, L.,Bockelmann, D.,Griesinger, C.,Koert, U. (deposition date: 2004-06-09, release date: 2004-07-13, Last modification date: 2019-09-25)

Primary citation

Xie, X.,Al-Momani, L.,Reiss, P.,Griesinger, C.,Koert, U.
An Asymmetric Ion Channel Derived from Gramicidin A. Synthesis, Function and NMR Structure.
FEBS J., 272:975-, 2005

PubMed Abstract: The biological ion channel gramicidin A (gA) was modified by synthetic means to obtain the tail-to-tail linked asymmetric gA-derived dimer compound 3. Single-channel current measurements for 3 in planar lipid bilayers exhibit an Eisenman I ion selectivity for alkali cations. The structural asymmetry does not lead to an observable functional asymmetry. The structure of 3 in solution without and with Cs cations was investigated by 1H-NMR spectroscopy. In CDCl3/CD3OH (1 : 1, v/v), 3 forms a mixture of double-stranded beta-helices. Upon addition of excess CsCl, the double-stranded species are converted completely into one new conformer: the right-handed single-stranded beta-helix. A combination of DQF-COSY and TOCSY was used for the assignment of the 1H-NMR spectrum of the Cs-3 complex in CDCl3/CD3OH (1 : 1, v/v). A total of 69 backbone, 27 long-range, and 64 side-chain distance restraints were obtained from NOESY together with 25 phi and 14 chi1 torsion angles obtained from coupling constants. These data were used as input for structure calculation with dyana built in sybyl 6.8. A final set of 11 structures with an average rmsd for the backbone of 0.45 A was obtained (PDB: 1TKQ). The structure of the Cs-3 complex in solution is equivalent to the bioactive channel conformation in the membrane environment.

PubMed: 15691331
DOI: 10.1111/J.1742-4658.2004.04531.X

Experimental method

SOLUTION NMR