Peptide name : Styelin D

Source/Organism : Asian sea squirt

Linear/Cyclic : Not found

Chirality : Not found

Peptide length: Not available

C-terminal modification: Not found

N-terminal modification : Amidation

Non-natural peptide information: W* : 6-bromotryptophan, R**: dihydroxyarginine, Y* : 3,4-dihydroxyphenylalanine, K* : 5-hydroxylysine, K** : dihydroxylysine

Assay type : MTT assay

Assay time : 20 h

Activity : IC50 : 10.1 mg/ml

Cell line : HCT-116

Cancer type : Human melanoma cancer

Other activity : Anti-bacterial activity

Amino Acid Composition Bar Chart : Not available

Molecular mass : Not available

Aliphatic index : Not available

Instability index : Not available

Hydrophobicity (GRAVY) : Not available

Isoelectric point : Not available

Charge (pH 7) : Not available

Aromaticity : Not available

Molar extinction coefficient (cysteine, cystine): Not available

Hydrophobic/hydrophilic ratio : Not available

hydrophobic moment : Not available

Missing amino acid : Not available

Most occurring amino acid : Not available

Most occurring amino acid frequency : Not available

Least occurring amino acid : Not available

Least occurring amino acid frequency : Not available

3D-structure: Not available

Secondary structure fraction (Helix, Turn, Sheet): Not available

SMILES Notation: Not available

Molecular descriptors: Not available

ADMET properties: Not available

1 : Taylor SW, et al. Styelin D, an extensively modified antimicrobial peptide from ascidian hemocytes. J Biol Chem. 2000; 275:38417-26. doi: 10.1074/jbc.M006762200

Paper title : Styelin D, an extensively modified antimicrobial peptide from ascidian hemocytes.

Doi : https://doi.org/10.1074/jbc.M006762200

Abstract : We isolated styelin D, a 32-residue, C-terminally amidated antimicrobial peptide, from the blood cells (hemocytes) of the solitary ascidian, Styela clava. Styelin D had remarkably extensive post-translational modifications, containing two novel amino acids, dihydroxyarginine and dihydroxylysine, and two distinctly unusual ones, 6-bromotryptophan and 3,4-dihydroxyphenylalanine. In addition, the peptide exhibited microheterogeneity because of differential mono- and dihydroxylation of several lysine residues. The primary sequence of one variant was: GW(*)LR(**)K(**)AAK(**)SVGK(**)FY(*)Y(*)K(**)HK(*)Y(*) Y(*)IK(*)AAWQIG KHAL-NH(2), where W(*) is 6-bromotryptophan, R(**) is dihydroxyarginine, Y(*) is 3,4-dihydroxyphenylalanine, K(*) is 5-hydroxylysine, and K(**) is dihydroxylysine. Styelin D exhibited activity against Gram-negative and Gram-positive bacteria, and this activity was retained in 200 mm NaCl. The role of the extensive modifications may be to preserve activity at low pH and/or high salinity because, under these conditions, the native peptide was considerably more active against the Gram-positive bacterial strains than its unmodified synthetic analogue. The peptide was also hemolytic and quite cytotoxic to eukaryotic cells. These broad ranging activities, combined with its relative abundance in ascidian hemocytes, suggest that styelin D plays a significant role in the innate immune mechanisms of S. clava.