The peptaibol antiamoebin as a model ion channel: similarities to bacterial potassium channels

Antiamoebin (AAM) is a polypeptide antibiotic that is capable of forming ion channels in phospholipid membranes; planar bilayer studies have suggested the channels are octamers. The crystal structure of a monomeric form of AAM has provided the basis for molecular modelling of an octameric helical bundle channel. The channel model is funnel‐shaped due to a substantial bend in the middle of the polypeptide chain caused by the presence of several imino acids. Inter‐monomer hydrogen bonds orientate a ring of glutamine side chains to form a constriction in the pore lumen. The channel lumen is lined both by side chains of Gln11 and by polypeptide backbone carbonyl groups. Electrostatic calculations on the model are compatible with a channel that transports cations across membranes.

[1]  G. Boheim.  Statistical analysis of alamethicin channels in black lipid membranes , 2005, The Journal of Membrane Biology.

[2]  B. Wallace,et al.  The peptaibol database: a sequence and structure resource , 2003, Journal of peptide science : an official publication of the European Peptide Society.

[3]  J. Chugh,et al.  Model for a helical bundle channel based on the high-resolution crystal structure of trichotoxin_A50E. , 2002, Biochemistry.

[4]  Youxing Jiang,et al.  Crystal structure and mechanism of a calcium-gated potassium channel , 2002, Nature.

[5]  Youxing Jiang,et al.  The open pore conformation of potassium channels , 2002, Nature.

[6]  B. Wallace,et al.  Antiamoebin: A polypeptide ion carrier and channel , 2002 .

[7]  B. Wallace,et al.  Peptaibols: models for ion channels. , 2001, Biochemical Society transactions.

[8]  B. Wallace.  Common structural features in gramicidin and other ion channels , 2000, BioEssays : news and reviews in molecular, cellular and developmental biology.

[9]  Robert W. Janes,et al.  Tryptophans in Membrane Proteins , 1999 .

[10]  B. Wallace,et al.  Antiamoebin can function as a carrier or as a pore-forming peptaibol. , 1998, Biochimica et biophysica acta.

[11]  T. Blundell,et al.  The structure and function of antiamoebin I, a proline-rich membrane-active polypeptide. , 1998, Structure.

[12]  I. Karle,et al.  Crystal structure of the channel-forming polypeptide antiamoebin in a membrane-mimetic environment. , 1998, Proceedings of the National Academy of Sciences of the United States of America.

[13]  B. Chait,et al.  The structure of the potassium channel: molecular basis of K+ conduction and selectivity. , 1998, Science.

[14]  E. Perozo,et al.  pH-dependent gating in the Streptomyces lividans K+ channel. , 1998, Biochemistry.

[15]  E A Merritt,et al.  Raster3D: photorealistic molecular graphics. , 1997, Methods in enzymology.

[16]  B. Wallace,et al.  HOLE: a program for the analysis of the pore dimensions of ion channel structural models. , 1996, Journal of molecular graphics.

[17]  D. Cafiso.  Alamethicin: a peptide model for voltage gating and protein-membrane interactions. , 1994, Annual review of biophysics and biomolecular structure.

[18]  K. Sharp,et al.  Protein folding and association: Insights from the interfacial and thermodynamic properties of hydrocarbons , 1991, Proteins.

[19]  P. Kraulis.  A program to produce both detailed and schematic plots of protein structures , 1991 .

[20]  J. Flippen-Anderson,et al.  Crystal structure of [Leu1]zervamicin, a membrane ion-channel peptide: implications for gating mechanisms. , 1991, Proceedings of the National Academy of Sciences of the United States of America.

[21]  M. Sansom.  The biophysics of peptide models of ion channels. , 1991, Progress in biophysics and molecular biology.

[22]  Alan R. Fersht,et al.  Stabilization of protein structure by interaction of α-helix dipole with a charged side chain , 1988, Nature.

[23]  M. Cascio,et al.  Conformation of alamethicin in phospholipid vesicles: Implications for insertion models , 1988, Proteins.

[24]  P. Balaram,et al.  The stereochemistry of peptides containing alpha-aminoisobutyric acid. , 1984, CRC critical reviews in biochemistry.

[25]  Frederic M. Richards,et al.  A voltage-gated ion channel model inferred from the crystal structure of alamethicin at 1.5-Å resolution , 1982, Nature.

[26]  V A Parsegian,et al.  ION‐MEMBRANE INTERACTIONS AS STRUCTURAL FORCES , 1975, Annals of the New York Academy of Sciences.

[27]  B. Lee,et al.  The interpretation of protein structures: estimation of static accessibility. , 1971, Journal of molecular biology.