Structural basis for endotoxin neutralisation and anti-inflammatory activity of thrombin-derived C-terminal peptides

Abstract

Thrombin-derived C-terminal peptides (TCPs) of about 2 kDa are present in wounds, where they exert anti-endotoxic functions. Employing a combination of nuclear magnetic resonance spectroscopy (NMR), biophysical, mass spectrometry and cellular studies combined with in silico multiscale modelling, we here determine the bound conformation of HVF18 (HVFRLKKWIQKVIDQFGE), a TCP generated by neutrophil elastase, in complex with bacterial lipopolysaccharide (LPS) and define a previously undisclosed interaction between TCPs and human CD14. Further, we show that TCPs bind to the LPS-binding hydrophobic pocket of CD14 and identify the peptide region crucial for TCP interaction with LPS and CD14. Taken together, our results demonstrate the role of structural transitions in LPS complex formation and CD14 interaction, providing a molecular explanation for the previously observed therapeutic effects of TCPs in experimental models of bacterial sepsis and endotoxin shock.

Thanatin: An Emerging Host Defense Antimicrobial Peptide with Multiple Modes of Action

“…Three-D structures of AMPs can be determined in solutions of LPS micelles using tr-NOESY NMR [ 61 , 62 , 63 , 64 ]. Also, the LPS-interacting residues of AMPs are determined at atomic resolution by STD-NMR [ 65 , 66 , 67 , 68 ].…”

High-Throughput Identification of Putative Antimicrobial Peptides from Multi-Omics Data of the Lined Seahorse (Hippocampus erectus)

“…In fact, TCPs usually aggregate with lipopolysaccharide (LPS) and Gram-negative bacteria to form an amorphous amyloid-like substance, contributing to the clearance of those aggregates by phagocytosis [39]. Recently, a high structure resolution of TCPs revealed the vital peptide regions for interaction with LPS and CD14, providing a detailed molecular explanation for the practical antimicrobial activities of TCPs [40]. The histone family, the second major group with the mapping of known AMPs in the present study, consists of histones H2A, H4, H3, and H2B.…”

Direct Measurement of Through‐Bond Effects in Molecular Multivalent Interactions

“…Thrombin aptamers are the most frequently used model system in proof‐of‐principle studies . Thrombin, a multifunctional serine protease, plays very important roles in procoagulant and anticoagulant reactions . The first aptamer binding to human α‐thrombin is a 15‐base‐long oligonucleotide (5′‐GGT TGG TGT GGT TGG‐3′, HD1), a DNA that adopts a chair‐like G‐quadruplex structure and interacts with the fibrinogen‐recognition exosite I .…”