ISSN:
0887-3585
Keywords:
α-helix
;
EPR
;
trypsinolysis
;
Chemistry
;
Biochemistry and Biotechnology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Medicine
Notes:
Colicin E1 is an E. coli plasmid-lencoded water-soluble protein that spontaneously inserts into lipid membranes to form a voltage-gated ion channel. We have employed a novel approach is which site-directed mutagenesis is used to provide highly specific attachment points for nitroxide spin labels. A series of colicin mutants, differing only by the position of a single cysteine residue, were prepared and selectively labeled at that cysteine. A hydrophilic sequence (398-406) within the C-terminal domain of the water-soluble form of the protein was investigated and exhibited an electron paramagnetic resonancc (EPR) spectral periodicity strongly suggesting an amphiphilic α-helix. After removal of the N—terminus of the protein with trypsin, the spectra for this sequence indicate increased label mobility and a more flexible structure.
Additional Material:
7 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/prot.340060312
