1GMK

GRAMICIDIN/KSCN COMPLEX

Summary for 1GMK

• Entry DOI: 10.2210/pdb1gmk/pdb
• Related: 1AL4 1ALX 1ALZ 1AV2 1BDW 1C4D 1GRM 1JNO 1JO3 1JO4 1KQE 1MAG 1MIC 1NG8 1NRM 1NRU 1NT5 1NT6 1TK2 1TKQ 1W5U 2IZQ 2XDC 3L8L
• Related PRD ID: PRD_000150
• Descriptor: GRAMICIDIN A, POTASSIUM ION, THIOCYANATE ION, ... (4 entities in total)
• Functional Keywords: gramicidin, antifungal, antibacterial, antibiotic, membrane ion channel, linear gramicidin, double helix
• Biological source: BREVIBACILLUS BREVIS
• Total number of polymer chains: 4
• Total formula weight: 8718.95

Authors

Doyle, D.A.,Wallace, B.A. (deposition date: 1996-07-09, release date: 1998-07-01, Last modification date: 2024-10-30)

Primary citation

Doyle, D.A.,Wallace, B.A.
Crystal Structure of the Gramicidin/Potassium Thiocyanate Complex.
J.Mol.Biol., 266:963-, 1997

PubMed Abstract: The hydrophobic channel-forming polypeptide gramicidin adopts a left-handed antiparallel double helix conformation with 6.4 residues per turn when in complex with monovalent cation salts in a methanol environment. The crystal structure of the gramicidin/potassium thiocyanate complex (a = 32.06 A, b = 51.80 A, and c = 31.04 A; space group P2(1)2(1)2(1)) has been solved to 2.5 A with an R-factor of 0.193. In the structure, binding sites for the cations are formed by the polypeptide backbone carbonyl groups tilting away from the helix axis toward the ions located in the central lumen. The polypeptide backbone conformations and the side-chain orientations in this potassium complex are significantly different from those in the previously solved gramicidin/caesium chloride crystal complex, due to the requirements for interactions with the smaller sized potassium cation. The locations and numbers of potassium binding sites also differ considerably from the locations and numbers of caesium binding sites in the other structure. Combining information from all the cation binding sites in the two gramicidin/ion complexes produces different views of the three-dimensional structures of a cation as it is transported along a transmembrane pore, and provides an experimental structural basis for modeling the dynamics of peptide-ion binding and ion transport.

PubMed: 9086274
DOI: 10.1006/JMBI.1996.0837

Experimental method

X-RAY DIFFRACTION (2.5 Å)