Chemistry:Pseudin
Pseudin is a peptide derived from Pseudis paradoxa.[1] Pseudins have some antimicrobial function.[2][3] There are several different forms:
- pseudin-1[4]
- pseudin-2 -- has been proposed as a treatment for type 2 diabetes.[5][6]
- pseudin-4[7]
Pseudin-2
Pseudin-2 is the most abundant version of the pseudins found on the skin of the paradoxical frog.[8] The primary sequence reads as GLNALKKVFQGIHEAIKLINNHVQ. Its secondary/tertiary structure consists of one cationic amphipathic α-helix.[8][9]
Antibacterial activity
Pseudin-2 was shown to have potent antibacterial activity, but a lower cytotoxicity.[8] The cytotoxicity of a peptide can be measured by its effect on human erythrocytes.[9] It takes a lower concentration of Pseudin-2 to kill bacteria or fungi such as E. coli, S. aureus, and C. albicans than to kill human erythrocytes.[8] It is hypothesized that Pseudin-2 binding to the cell membrane of the bacteria results in a conformational change in which the peptide forms an α-helical shape, which allows it to perform cell lysis by inserting itself in the hydrophobic portion of the membrane.[8][9] This mechanism is applicable to similar amphipathic α-helical peptides created by many frog species, although most of these peptides aren't very potent against bacteria.[10] By increasing the cationicity and amphipathic nature of the molecule, it is possible to create analogues of Pseudin-2 that are even more selective towards bacteria. This is done by substituting leucine residues with lysine residues and glycine residues with proline residues, which results in two shorter α-helices (linked by the substituted proline) that are more attuned to penetrating bacterial cell membranes.[9]
See also
References
- ↑ "InterPro: IPR013156 Pseudin antimicrobial peptide". http://www.embl-ebi.ac.uk/interpro/DisplayIproEntry?ac=IPR013156.
- ↑ senior reporters; G.C. Barrett; J.S. Davies. (2004). Amino acids, peptides and proteins. Cambridge, Eng: Royal Society of Chemistry. pp. 72. ISBN 0-85404-242-3. https://archive.org/details/aminoacidspeptid00davi_112.
- ↑ Rinaldi AC (2002). "Antimicrobial peptides from amphibian skin: an expanding scenario". Curr Opin Chem Biol 6 (6): 799–804. doi:10.1016/S1367-5931(02)00401-5. PMID 12470734.
- ↑ "Pseudin-1 - Pseudis paradoxa (Paradoxical frog)". http://beta.uniprot.org/uniprot/P83188.
- ↑ "Insulin-releasing properties of the frog skin peptide pseudin-2 and its [Lys(18)]-substituted analogue". Biol. Chem. 389 (2): 143–8. 2008. doi:10.1515/BC.2008.018. PMID 18163889.
- ↑ Rose, David (2008-03-03). "Jungle frog's anti-infection agent may help millions of diabetics - Times Online". The Times (London). http://www.timesonline.co.uk/tol/news/uk/science/article3471372.ece.
- ↑ "Pseudin-4 - Pseudis paradoxa (Paradoxical frog)". http://beta.uniprot.org/uniprot/P83191.
- ↑ 8.0 8.1 8.2 8.3 8.4 Olson, L.; Soto, A. M.; Knoop, F. C.; Conlon, J. M. (2001-11-09). "Pseudin-2: an antimicrobial peptide with low hemolytic activity from the skin of the paradoxical frog". Biochemical and Biophysical Research Communications 288 (4): 1001–1005. doi:10.1006/bbrc.2001.5884. ISSN 0006-291X. PMID 11689009. https://pubmed.ncbi.nlm.nih.gov/11689009/.
- ↑ 9.0 9.1 9.2 9.3 Jeon, Dasom; Jeong, Min-Cheol; Jacob, Binu; Bang, Jeong Kyu; Kim, Eun-Hee; Cheong, Chaejoon; Jung, In Duk; Park, Yoonkyung et al. (2017-05-03). "Investigation of cationicity and structure of pseudin-2 analogues for enhanced bacterial selectivity and anti-inflammatory activity" (in en). Scientific Reports 7 (1): 1455. doi:10.1038/s41598-017-01474-0. ISSN 2045-2322. PMID 28469145. Bibcode: 2017NatSR...7.1455J.
- ↑ Conlon, J. Michael (2011-07-11). "Structural diversity and species distribution of host-defense peptides in frog skin secretions". Cellular and Molecular Life Sciences 68 (13): 2303–2315. doi:10.1007/s00018-011-0720-8. ISSN 1420-9071. PMID 21560068. https://pubmed.ncbi.nlm.nih.gov/21560068/.
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