Peptide name : LL-37(1-4,17-27)

Source/Organism : LL-37,a series of peptide fragments

Linear/Cyclic : Linear

Chirality : L

Peptide length: 15

C-terminal modification: Linear

N-terminal modification : Free

Non-natural peptide information: None

Assay type : MTT/MTS assay

Assay time : 24h

Activity : Not found

Cell line : HBMEC

Cancer type : Prostate cancer

Other activity : Anti-microbial activity

Amino acid composition bar chart :

Molecular mass : 1848.1956 Dalton

Aliphatic index : 1.233

Instability index : -0.3267

Hydrophobicity (GRAVY) : -0.086

Isoelectric point : 9.9862

Charge (pH 7) : 1.7603

Aromaticity : 0.133

Molar extinction coefficient (cysteine, cystine): (0, 0)

Hydrophobic/hydrophilic ratio : 1.14285714

hydrophobic moment : 1.8553

Missing amino acid : C,W,H,T,P,M,E,S,Y,N,A

Most occurring amino acid : L

Most occurring amino acid frequency : 2

Least occurring amino acid : G

Least occurring amino acid frequency : 1

Secondary structure fraction (Helix, Turn, Sheet): (0.2, 0.2, 0.4)

SMILES Notation: CC[C@H](C)[C@H](NC(=O)[C@H](CCCNC(=N)N)NC(=O)[C@H](CCC(N)=O)NC(=O)[C@@H](NC(=O)[C@@H](NC(=O)[C@H](CCCNC(=N)N)NC(=O)[C@H](CCCCN)NC(=O)[C@H](Cc1ccccc1)NC(=O)[C@H](CC(=O)O)NC(=O)CNC(=O)[C@H](CC(C)C)NC(=O)[C@@H](N)CC(C)C)[C@@H](C)CC)C(C)C)C(=O)N[C@@H](CCCCN)C(=O)N[C@@H](CC(=O)O)C(=O)N[C@@H](Cc1ccccc1)C(=O)O

1 : Li X, et al. Solution structures of human LL-37 fragments and NMR-based identification of a minimal membrane-targeting antimicrobial and anticancer region. J Am Chem Soc. 2006; 128:5776-85. doi: 10.1021/ja0584875

Paper title : Solution structures of human LL-37 fragments and NMR-based identification of a minimal membrane-targeting antimicrobial and anticancer region.

Doi : https://doi.org/10.1021/ja0584875

Abstract : To understand the structure and activity relationship of human LL-37, a series of peptide fragments was designed. The N-terminal fragment, LL-37(1-12), was not active, while the C-terminal fragment, LL-37(13-37), killed Escherichia coli, as well as drug-sensitive and drug-resistant cancer cells. A 13-residue core antibacterial and anticancer peptide, corresponding to residues 17-29 of LL-37, was identified based on total correlated spectroscopy by trimming nonessential regions (TOCSY-trim). Because LL-37 acts on bacterial membranes, three-dimensional structures of its fragments were determined in micelles by NMR, including structural refinement by natural abundance 15N and 13C chemical shifts. Aromatic-aromatic interactions in the N-terminal fragment were proposed to be essential for LL-37 aggregation. The LL-37 core peptide adopts a similar structure in the micelles of SDS or dioctanoyl phosphatidylglycerol. This structure is retained in the C-terminal fragment LL-37(13-37) and very likely in intact LL-37 based on peptide-aided signal assignments. The higher antibacterial activity of the LL-37 core peptide than aurein 1.2 was attributed to additional cationic residues. To achieve selective membrane targeting, D-amino acids were incorporated into LL-37(17-32). While the D-peptide showed similar antibacterial activity to the L-diastereomer, it lost toxicity to human cells. Structural analysis revealed hydrophobic defects in the new amphipathic structure of the D-peptide, leading to a much shorter retention time on a reversed-phase HPLC column. It is proposed that hydrophobic defects as a result of incoherent hydrophobic packing provide a structural basis for the improvement in cell selectivity of the LL-37 fragment.