Peptide name : Chensinin-1b

Source/Organism : Designed based on Chensinin-1

Linear/Cyclic : Cyclic

Chirality : Not found

Peptide length: 18

C-terminal modification: Cyclic

N-terminal modification : Free

Non-natural peptide information: None

Assay type : Not specified

Assay time : Not found

Activity : Not found

Cell line : Not found

Cancer type : Not found

Other activity : Anti-bacterial activity; Hemolytic activity

Amino acid composition bar chart :

Molecular mass : 2551.9206 Dalton

Aliphatic index : 0.433

Instability index : 54.0889

Hydrophobicity (GRAVY) : -1.672

Isoelectric point : 12

Charge (pH 7) : 5.8078

Aromaticity : 0.222

Molar extinction coefficient (cysteine, cystine): (16500, 16500)

Hydrophobic/hydrophilic ratio : 0.63636363

hydrophobic moment : -1.271

Missing amino acid : C,Q,T,P,M,I,E,D,Y,N,G

Most occurring amino acid : R

Most occurring amino acid frequency : 5

Least occurring amino acid : S

Least occurring amino acid frequency : 1

Secondary structure fraction (Helix, Turn, Sheet): (0.1, 0.0, 0.3)

SMILES Notation: CC(C)C[C@H](NC(=O)[C@H](CCCNC(=N)N)NC(=O)[C@H](Cc1c[nH]cn1)NC(=O)[C@H](C)NC(=O)[C@H](CCCNC(=N)N)NC(=O)[C@H](Cc1c[nH]cn1)NC(=O)[C@H](Cc1c[nH]c2ccccc12)NC(=O)[C@H](Cc1ccccc1)NC(=O)[C@H](CCCNC(=N)N)NC(=O)[C@H](CCCNC(=N)N)NC(=O)[C@H](Cc1c[nH]c2ccccc12)NC(=O)[C@H](Cc1c[nH]cn1)NC(=O)[C@H](CCCNC(=N)N)NC(=O)[C@H](Cc1c[nH]c2ccccc12)NC(=O)[C@@H](NC(=O)[C@H](CCCCN)NC(=O)[C@@H](N)CO)C(C)C)C(=O)N[C@@H](Cc1c[nH]cn1)C(=O)O

1 : Dong W, et al. Structure-activity analysis and biological studies of chensinin-1b analogues. Acta Biomater. 2016; 37:59-68. doi: 10.1016/j.actbio.2016.04.003

Paper title : Structure-activity analysis and biological studies of chensinin-1b analogues.

Doi : https://doi.org/10.1016/j.actbio.2016.04.003

Abstract : UNLABELLED: Chensinin-1b shows a potent and broad-spectrum bactericidal activity and no hemolytic activity and thus is a potential therapeutic agent against bacterial infection. The NMR structure of chensinin-1b consists of a partially α-helical region (residues 8-14) in a membrane-mimic environment that is distinct from other common antimicrobial peptides. However, further analysis of the structural features of chensinin-1b is required to better understand its bactericidal activity. In this study, a series of N- and C-terminally truncated or amino acid-substituted chensinin-1b analogues were synthesized. Next, the bactericidal activity and bacterial membrane effects of the analogues were investigated. The results indicated that the N-terminal residues play a more significant role than the C-terminal residues in the antimicrobial activity of chensinin-1b. The removal of five amino acids from the C-terminus of chensinin-1b did not affect its biological properties, but helix disruption significantly decreased bactericidal activity. The substitution of positively charged residues increased the helicity and antimicrobial activity of the peptide. We also identified a novel analogue [R(4),R(10)]C1b(3-13) that exhibited similar bactericidal properties with its parent peptide chensinin-1b. Electrostatic interactions between the selected analogues and lipopolysaccharides or cells were detected using isothermal titration calorimetry or zeta potential. The thermodynamic parameters ΔH and ΔS for [R(4),R(10)]C1b(3-13) were -20.48kcalmol(-1) and -0.0408kcalmol(-1)deg(-1), respectively. Chensinin-1b yielded similar results of -26.36kcalmol(-1) and -0.0559kcalmol(-1)deg(-1) for ΔH and ΔS, respectively. These results are consistence with their antimicrobial activities. Lastly, membrane depolarization studies showed that selected analogues exerted bactericidal activity by damaging the cytoplasmic membrane. STATEMENT OF SIGNIFICANCE: Antimicrobial peptide chensinin-1b is a candidate for the development of new drugs and a template for the design of synthetic analogues. It mainly exhibits a random coil conformation in membrane environment, and in this manuscript, we characterized the structure of chensinin-1b using NMR spectroscopy, its structure is different than the structures of magainin 2, which has an α-helical conformation and indolicidin, which has a random coil structure. The structural features of chensinin-1b that are required for its potent bactericidal activity were also elucidated. Based on these data, we can fully understand the structure-activity relationship of such peptide and identified a novel analogue with properties that make it an attractive topic for future therapeutic research.