Colicin la channel domain

To avoid complication from extensively labeled amino acids from either [l-I3C]glucose or [2-13C]glycerol, Hong and Jakes utilized growth media supplemented with unlabeled amino acid products of the citric acid cycle in order to obtain simplified l3C NMR spectra of the colicin la channel domain.8111... 

D. Huster, L. Xiao, M. Hong, Sohd-state NMR investigation of the dynamics of the soluble and membrane-bound colicin la channel-forming domain. Biochemistry 40 (2001) 7662-7674. 

Interestingly, certain other pore-forming toxins possess helix-bundle motifs that may participate in channel formation, in a manner similar to that proposed for colicin la. For example, the S-endotoxui produced by Bacillus thuringiensis is toxic to Coleoptera insects (beetles) and is composed of three domains, including a seven-helix bundle, a three-sheet domain, and a /3-sandwich. In the seven-helix bundle, helix 5 is highly hydrophobic, and the other six helices are amphipathic. In solution (Figure 10.32), the six amphipathic... 

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