Solution and solid-state NMR structural investigations of the antimicrobial designer peptide GL13K in membranes.
 

Solution and solid-state NMR structural investigations of the antimicrobial designer peptide GL13K in membranes.

Related Articles Solution and solid-state NMR structural investigations of the antimicrobial designer peptide GL13K in membranes.

Biochemistry. 2017 Jul 12;:

Authors: Harmouche N, Aisenbrey C, Porcelli F, Xia Y, Nelson SED, Chen X, Raya J, Vermeer LS, Aparicio C, Veglia G, Gorr SU, Bechinger B

Abstract
The antimicrobial peptide GL13K encompasses 13 amino acid residues and has been designed and optimized from the salivary protein BPIFA2 to exhibit potent bacteriocidal and anti-biofilm activity against Gram-negative and Gram-positive bacteria as well as anti-lipopolysaccharide activity in vitro and in vivo. Here, the peptide was analyzed in a variety of membrane environments by CD spectroscopy and by high resolution multidimensional solution NMR spectroscopy. Whereas in the absence of membranes a random coil conformation predominates, the peptide adopts a helical structure from residues 5 to 11 in the presence of DPC micelles. In contrast, a predominantly beta-sheet structure was observed in the presence of lipid bilayers carrying negatively charged phospholipids. Whereas 15N solid-state NMR spectra are indicative of a partial alignment of the peptide 15N-1H vector along the membrane surface, 2H and 31P solid-state NMR indicate that in this configuration the peptide exhibits pronounced disordering activities on the phospholipid membrane, which possibly relates to antimicrobial action. GL13K, thus, undergoes a number of conformational transitions including a random coil state in solution, a helical structure when diluted at the surface of zwitterionic membranes, and beta-sheet conformations when occurring at high peptide-to-lipid ratio.


PMID: 28699734 [PubMed - as supplied by publisher]



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