Download MendeleyStructural and Dynamic Insights into a Glycine-Mediated Short Analogue of a Designed Peptide in Lipopolysaccharide Micelles: Correlation Between Compact Structure and Anti-Endotoxin Activity.
Datta, A., Jaiswal, N., Ilyas, H., Debnath, S., Biswas, K., Kumar, D., Bhunia, A.(2017) Biochemistry 56: 1348-1362
- PubMed: 28168875 Search on PubMed
- DOI: https://doi.org/10.1021/acs.biochem.6b01229
- Primary Citation Related Structures:
5WRX - PubMed Abstract:
In this study, we report an interaction study of a 13-residue analogue peptide VG13P (VARGWGRKCPLFG), derived from a designed VG16KRKP peptide (VARGWKRKCPLFGKGG), with a Lys6Gly mutation and removal of the last three residues Lys 14 -Gly 15 -Gly 16 , in lipopolysaccharide (LPS), a major component of the outer membrane of Gram-negative bacteria and responsible for sepsis or septic shock. VG13P displays an enhanced anti-endotoxin property as evident from significant reduction in LPS-induced TNF-α gene expression levels in a monocytic cell line, while it retains almost unchanged antimicrobial activity as its parent VG16KRKP against Gram-negative bacterial as well as fungal pathogens. In addition, in vitro LPS binding properties of VG13P in comparison to its parent VG16KRKP also remained unhindered, suggesting that the flexible C-terminal end of VG16KRKP may not play a major role in its observed antibacterial and LPS binding properties. An NMR-resolved solution structure of VG13P in LPS reveals two consecutive β-turns: one at the N-terminus, followed by another at the central region, closely resembling a rocking chair. The crucial Lys6Gly mutation along with C-terminal truncation from VG16KRKP reorients the hydrophobic hub in VG13P in a unique way so as to fold the N-terminal end back on itself, forming a turn and allowing Val1 and Ala2 to interact with Leu11 and Phe12 to bring the hydrophobic residues closer together to form a more compact hub compared to its parent. The hub is further strengthened via CH-π interaction between Gly4 and Phe12. This accounts for its improved anti-endotoxin activity as well as to its uninterrupted antimicrobial activity.
- Center of Biomedical Research , SGPGIMS Campus, Lucknow 226014, India.
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