Antimicrobial peptides: Difference between revisions
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Antimicrobial peptides are divided into subgroups on the basis of their amino acid composition and structure (ref nature review). | Antimicrobial peptides are divided into subgroups on the basis of their amino acid composition and structure (ref nature review). | ||
(1) | (1)'''Anionic peptides''' | ||
• Maximin H5 from amphibians. | • Maximin H5 from amphibians. | ||
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• Dermcidin from humans147. | • Dermcidin from humans147. | ||
(2) Linear cationic α-helical peptides - contains ~290 cationic peptides, which are short (contain <40 amino acid residues), lack | (2) '''Linear cationic α-helical peptides''' - contains ~290 cationic peptides, which are short (contain <40 amino acid residues), lack | ||
cysteine residues and sometimes have a hinge or ‘kink’ in the middle | cysteine residues and sometimes have a hinge or ‘kink’ in the middle | ||
In aqueous solutions many of these peptides are disordered, but in the presence of trifluoroethanol,sodium dodecyl sulphate (SDS) micelles, phospholipid vesicles and liposomes, or Lipid A, all or part of the molecule is converted to an α-helix. | In aqueous solutions many of these peptides are disordered, but in the presence of trifluoroethanol,sodium dodecyl sulphate (SDS) micelles, phospholipid vesicles and liposomes, or Lipid A, all or part of the molecule is converted to an α-helix. | ||
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• Small histidine-rich salivary polypeptides, including the histatins from man and some higher primates116. | • Small histidine-rich salivary polypeptides, including the histatins from man and some higher primates116. | ||
(4) Anionic and cationic peptides that contain cysteine and form disulphide bonds - this group has ~380 members, contain cysteine residues and form disulphide bonds and stable β-sheets. | (4)''' Anionic and cationic peptides that contain cysteine and form disulphide bonds''' - this group has ~380 members, contain cysteine residues and form disulphide bonds and stable β-sheets. | ||
A diverse family of defensins is belong to this group. | A diverse family of defensins is belong to this group. | ||
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• Peptides with >3 disulphide bonds include drosomycin in fruit flies and plant antifungal defensins. | • Peptides with >3 disulphide bonds include drosomycin in fruit flies and plant antifungal defensins. | ||
'''(5) Anionic and cationic peptide fragments of larger proteins''' - these fragments have antimicrobial activity and are similar in composition and structure to the antimicrobial peptides described above. However, their role in innate immunity is not yet clear. | |||
• Lactoferricin from lactoferrin. | |||
• Casocidin I from human casein. | |||
• Antimicrobial domains from bovine α-lactalbumin, human haemoglobin, lysozyme and ovalbumin. | |||
