Fourier transform infrared spectroscopy reveals a rigid alpha-helical assembly for the tetrameric Streptomyces lividans K+ channel.
The structure of the tetrameric K+ channel from Streptomyces lividans in a lipid bilayer environment was studied by polarized attenuated total reflection Fourier transform infrared spectroscopy. The channel displays approximately 43% alpha-helical and 25% beta-sheet content. In addition, H/D exchange experiments show that only 43% of the backbone amide protons are exchangeable with solvent. On average, the alpha-helices are tilted 33 degrees normal to the membrane surface. The results are discussed in relationship to the lactose permease of Escherichia coli, a membrane transport protein.
le Coutre
J
J
Howard Hughes Medical Institute, Departments of Physiology and Microbiology and Molecular Genetics, Molecular Biology Institute, University of California, Los Angeles, CA 90095-1662, USA. lecoutre@hhmi.ucla.edu
Kaback
H R
HR
Patel
C K
CK
Heginbotham
L
L
Miller
C
C
D008051:Lipid Bilayers; D015221:Potassium Channels / Q000737:chemistry*; D017510:Protein Folding; D019265:Spectroscopy, Near-Infrared; D013302:Streptomyces / Q000378:metabolism*
D008051:Lipid Bilayers; D015221:Potassium Channels