Peptide name : RP9

Source/Organism : Siamese crocodile leukocyte extract

Linear/Cyclic : Not found

Chirality : Not found

Peptide length: 9

C-terminal modification: Not found

N-terminal modification : Free

Non-natural peptide information: None

Assay type : Sulforhodamine B colorimetric assay, apoptosis array assay

Assay time : 24h

Activity : IC50 :168.3 μM

Cell line : CaSki

Cancer type : Cervical cancer

Other activity : Anti-microbial activity

Amino acid composition bar chart :

Molecular mass : 951.0811 Dalton

Aliphatic index : 0.977

Instability index : 20.8556

Hydrophobicity (GRAVY) : -0.2

Isoelectric point : 9.7565

Charge (pH 7) : 0.8473

Aromaticity : 0

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

Hydrophobic/hydrophilic ratio : 1.25

hydrophobic moment : 0.6179

Missing amino acid : C,W,Q,M,I,E,K,F,D,Y,N,V

Most occurring amino acid : L

Most occurring amino acid frequency : 2

Least occurring amino acid : R

Least occurring amino acid frequency : 1

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

SMILES Notation: CC(C)C[C@H](NC(=O)[C@H](C)NC(=O)[C@H](CO)NC(=O)CNC(=O)[C@@H](N)CCCNC(=N)N)C(=O)N[C@H](C(=O)N[C@@H](Cc1c[nH]cn1)C(=O)N[C@@H](CC(C)C)C(=O)N1CCC[C@H]1C(=O)O)[C@@H](C)O

1 : Theansungnoen T, et al. Cationic Antimicrobial Peptides Derived from Crocodylus siamensis Leukocyte Extract, Revealing Anticancer Activity and Apoptotic Induction on Human Cervical Cancer Cells. Protein J. 2016; 35:202-11. doi: 10.1007/s10930-016-9662-1

Paper title : Cationic Antimicrobial Peptides Derived from Crocodylus siamensis Leukocyte Extract, Revealing Anticancer Activity and Apoptotic Induction on Human Cervical Cancer Cells.

Doi : https://doi.org/10.1007/s10930-016-9662-1

Abstract : Known antimicrobial peptides KT2 and RT2 as well as the novel RP9 derived from the leukocyte extract of the freshwater crocodile (Crocodylus siamensis) were used to evaluate the ability in killing human cervical cancer cells. RP9 in the extract was purified by a combination of anion exchange column and reversed-phase HPLC, and its sequence was analyzed by mass spectrometry. The novel peptide could inhibit Gram-negative Vibrio cholerae (clinical isolation) and Gram-positive Bacillus pumilus TISTR 905, and its MIC values were 61.2 µM. From scanning electron microscopy, the peptide was seen to affect bacterial surfaces directly. KT2 and RT2, which are designed antimicrobial peptides using the C. siamensis Leucrocin I template, as well as RP9 were chemically synthesized for investigation of anticancer activity. By Sulforhodamine B colorimetric assay, these antimicrobial peptides could inhibit both HeLa and CaSki cancer cell lines. The IC50 values of KT2 and RT2 for HeLa and CaSki cells showed 28.7-53.4 and 17.3-30.8 µM, while those of RP9 were 126.2 and 168.3 µM, respectively. Additionally, the best candidate peptides KT2 and RT2 were used to determine the apoptotic induction on cancer cells by human apoptosis array assay. As a result, KT2 and RT2 were observed to induce apoptotic cell death in HeLa cells. Therefore, these results indicate that KT2 and RT2 with antimicrobial activity have a highly potent ability to kill human cervical cancer cells.